---

---

(a)	See reconciliation of this non-GAAP financial measure to net income (loss) and definition included herein.

(b)	As issued on October 18, 2017.

(c)	Attributable to CCIC common stockholders.

---

•

Lightower Acquisition. On November 1, 2017, Crown Castle completed its previously announced acquisition of LTS Group Holdings LLC ("Lightower"). When compared to the prior fourth quarter 2017 Outlook issued on October 18, 2017, which did not include any contribution from Lightower, the acquisition contributed approximately $140 million, $83 million, and $79 million to site rental revenues, Adjusted EBITDA and AFFO, respectively. Excluding these Lightower contributions, our results would have been within the ranges provided in the prior Outlook for site rental revenues, Adjusted EBITDA and AFFO.

•

Site rental revenues. Site rental revenues grew approximately 29%, or $234 million, from fourth quarter 2016 to fourth quarter 2017, inclusive of approximately $44 million in Organic Contribution to Site Rental Revenues plus $192 million in contributions from acquisitions and other items, less a $2 million reduction in straight-lined revenues. The $44 million in Organic Contribution to Site Rental Revenues represents approximately 5.5% growth, comprised of approximately 8% growth from new leasing activity and contracted tenant escalations, net of approximately 2.5% from tenant non-renewals. Site rental revenues for fourth quarter 2017 benefited from approximately $5 million associated with certain long-term customer agreements signed during the period that include a combination of contracted new leasing activity and term extensions on existing leases.

•	Net income. Net income for fourth quarter 2017 was $98 million.

•	Adjusted EBITDA and AFFO.  When compared to the prior fourth quarter 2017 Outlook, Adjusted EBITDA and AFFO for fourth quarter 2017 were impacted by approximately $10 million of higher costs associated with additional accruals for annual bonuses relating to full year 2017 results, and severance related expenses.

•	Capital expenditures and acquisitions. Capital expenditures during the quarter were approximately $377 million, comprised of approximately $15 million of land purchases, approximately $25 million of sustaining capital expenditures and approximately $337 million of revenue generating capital expenditures.

•	Common stock dividend. During the quarter, Crown Castle paid common stock dividends of approximately $427 million in the aggregate, or $1.05 per common share, an increase of approximately 11% on a per share basis compared to the same period a year ago.

(a)	See reconciliation of this non-GAAP financial measure to net income (loss) included herein.

(b)	As issued on October 18, 2017.

(c)	Attributable to CCIC common stockholders.

---

•

Site rental revenues. Site rental revenues grew approximately 13%, or $436 million, from full year 2016 to full year 2017, inclusive of approximately $160 million in Organic Contribution to Site Rental Revenues plus $323 million in contributions from acquisitions and other items, less a $47 million reduction in straight-line revenues. The $160 million in Organic Contribution to Site Rental Revenues represents approximately 5% growth, comprised of approximately 8% growth from new leasing activity and contracted tenant escalations, net of approximately 3% from tenant non-renewals.

•	Capital expenditures. Capital expenditures during the year were approximately $1.2 billion, comprised of approximately $81 million of land purchases, approximately $85 million of sustaining capital expenditures and approximately $1.1 billion of revenue generating capital expenditures.

•	Common stock dividend. During the year, Crown Castle paid common stock dividends of approximately $1.5 billion in the aggregate, or $3.90 per common share, an increase of approximately 8% on a per share basis compared to the same period a year ago.

---

(a)	Exclusive of depreciation, amortization and accretion.

(b)	See reconciliation of this non-GAAP financial measure to net income (loss) and definition included herein.

(c)	See reconciliation of "components of interest expense and amortization of deferred financing costs" herein for a discussion of non-cash interest expense.

(d)	Attributable to CCIC common stockholders.

(e)	Our AFFO for historical periods may not be comparable to those periods presented prospectively from and after January 1, 2018, including our Outlook for first quarter 2018 and full year 2018 herein. See "Sustaining capital expenditures" and "Integration capital expenditures" within "Non-GAAP Financial Measures, Segment Measures and Other Calculations" for further information.

(f)	The assumption for first quarter 2018 and full year 2018 diluted weighted-average common shares outstanding is based on diluted common shares outstanding as of December 31, 2017. For all periods presented, the diluted weighted-average common shares outstanding does not include any assumed conversion of the 6.875% Mandatory Convertible Preferred Stock in the share count.

(a)	See reconciliation of this non-GAAP financial measure to net income (loss) and definition included herein.

(b)	Our AFFO for historical periods may not be comparable to those periods presented prospectively from and after January 1, 2018, including our Outlook for first quarter 2018 and full year 2018 herein. See "Sustaining capital expenditures" and "Integration capital expenditures" within "Non-GAAP Financial Measures, Segment Measures and Other Calculations" for further information.

(c)	Attributable to CCIC common stockholders.

(d)	The assumption for full year 2018 diluted weighted-average common shares outstanding is based on diluted common shares outstanding as of December 31, 2017. For all periods presented, the diluted weighted-average common shares outstanding does not include any assumed conversion of the 6.875% Mandatory Convertible Preferred Stock in the share count.

(e)	As issued on October 18, 2017.

---

•	Consistent with the prior full year 2018 Outlook, the current Outlook does not include any anticipated contribution from the deployment of FirstNet.

•

The increase in full year 2018 Outlook reflects an expected increase in site rental revenues associated with certain long-term customer agreements signed during fourth quarter 2017 that include a combination of contracted new leasing activity and term extensions on existing leases. The prior full year 2018 Outlook included the expected increase in new leasing activity, but not the straight-line impact resulting from these agreements. As a result, the signing of these agreements is expected to impact site rental revenues, Adjusted EBITDA and net income.

•	The expected contribution from Lightower for full year 2018 remains unchanged, including $850 million to $870 million in site rental revenues, $510 million to $530 million in Adjusted EBITDA, and $465 million to $485 million in AFFO before financing costs.

•	The chart below reconciles the components of expected growth in site rental revenues from 2017 to 2018 of $910 million to $955 million, inclusive of expected Organic Contribution to Site Rental Revenues during 2018 of $185 million to $225 million.

•	For the above chart, the entire expected contribution to full year 2018 Outlook for growth in site rental revenues from Lightower is included within acquisitions, tower builds and other.

---

•	The chart below reconciles the components of expected growth in AFFO from 2017 to 2018 of between $360 million and $400 million.

•	Additional information is available in Crown Castle's quarterly Supplemental Information Package posted in the Investors section of its website.

---

•

Adjusted EBITDA is useful to investors or other interested parties in evaluating our financial performance. Adjusted EBITDA is the primary measure used by management (1) to evaluate the economic productivity of our operations and (2) for purposes of making decisions about allocating resources to, and assessing the performance of, our operations. Management believes that Adjusted EBITDA helps investors or other interested parties meaningfully evaluate and compare the results of our operations (1) from period to period and (2) to our competitors, by removing the impact of our capital structure (primarily interest charges from our outstanding debt) and asset base (primarily depreciation, amortization and accretion) from our financial results. Management also believes Adjusted EBITDA is frequently used by investors or other interested parties in the evaluation of the communications infrastructure sector and other REITs to measure financial performance without regard to items such as depreciation, amortization and accretion which can vary depending upon accounting methods and the book value of assets. In addition, Adjusted EBITDA is similar to the measure of current financial performance generally used in our debt covenant calculations. Adjusted EBITDA should be considered only as a supplement to net income computed in accordance with GAAP as a measure of our performance.

•

AFFO is useful to investors or other interested parties in evaluating our financial performance. Management believes that AFFO helps investors or other interested parties meaningfully evaluate our financial performance as it includes (1) the impact of our capital structure (primarily interest expense on our outstanding debt and dividends on our preferred stock) and (2) sustaining capital expenditures, and excludes the impact of our (a) asset base (primarily depreciation, amortization and accretion) and (b) certain non-cash items, including straight-lined revenues and expenses related to fixed escalations and rent free periods. GAAP requires rental revenues and expenses related to leases that contain specified rental increases over the life of the lease to be recognized evenly over the life of the lease. In accordance with GAAP, if payment terms call for fixed escalations, or rent free periods, the revenue or expense is recognized on a straight-lined basis over the fixed, non-cancelable term of the contract. Management notes that Crown Castle uses AFFO only as a performance measure. AFFO should be considered only as a supplement to net income computed in accordance with GAAP as a measure of our performance and should not be considered as an alternative to cash flows from operations or as residual cash flow available for discretionary investment.

•

FFO is useful to investors or other interested parties in evaluating our financial performance. Management believes that FFO may be used by investors or other interested parties as a basis to compare our financial performance with that of other REITs. FFO helps investors or other interested parties meaningfully evaluate financial performance by excluding the impact of our asset base (primarily depreciation, amortization and accretion). FFO is not a key performance indicator used by Crown Castle. FFO should be considered only as a supplement to net income computed in accordance with GAAP as a measure of our performance and should not be considered as an alternative to cash flow from operations.

---

•

Organic Contribution to Site Rental Revenues is useful to investors or other interested parties in understanding the components of the year-over-year changes in our site rental revenues computed in accordance with GAAP. Management uses the Organic Contribution to Site Rental Revenues to assess year-over-year growth rates for our rental activities, to evaluate current performance, to capture trends in rental rates, new leasing activities and customer non-renewals in our core business, as well to forecast future results. Organic Contribution to Site Rental Revenues is not meant as an alternative measure of revenue and should be considered only as a supplement in understanding and assessing the performance of our site rental revenues computed in accordance with GAAP.

---

---

(a)	See the reconciliation of "components of interest expense and amortization of deferred financing costs" herein for a discussion of non-cash interest expense.

(b)	See "Non-GAAP Financial Measures, Segment Measures and Other Calculations" herein for a discussion of our definition of Adjusted EBITDA.

(c)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

(a)	See the reconciliation of "components of historical interest expense and amortization of deferred financing costs" herein for a discussion of non-cash interest expense.

(b)	See "Non-GAAP Financial Measures, Segment Measures and Other Calculations" herein for a discussion of our definition of Adjusted EBITDA.

(c)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

---

(a)	See "Non-GAAP Financial Measures, Segment Measures and Other Calculations" herein for a discussion of our definitions of FFO and AFFO.

(b)	FFO and AFFO are reduced by cash paid for preferred stock dividends during the period in which they are paid.

(c)

Diluted weighted-average common shares outstanding were 408.1 million, 352.9 million, 383.2 million and 340.9 million for the three months ended December 31, 2017 and 2016 and the twelve months ended December 31, 2017 and 2016, respectively. For all periods presented, the diluted weighted-average common shares outstanding does not include any assumed conversion of the 6.875% Mandatory Convertible Preferred Stock in the share count.

(d)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

(e)	Attributable to CCIC common stockholders.

---

(a)	The assumption for first quarter 2018 and full year 2018 diluted weighted-average common shares outstanding is 408.1 million based on diluted common shares outstanding as of December 31, 2017. For all periods presented, the diluted weighted-average common shares outstanding does not include any assumed conversion of the 6.875% Mandatory Convertible Preferred Stock in the share count.

(b)	See "Non-GAAP Financial Measures, Segment Measures and Other Calculations" herein for a discussion for our definitions of FFO and AFFO.

(c)	FFO and AFFO are reduced by cash paid for preferred stock dividends during the period in which they are paid.

(d)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

(e)	Attributable to CCIC common stockholders.

(f)	Our AFFO for historical periods may not be comparable to those periods presented prospectively from and after January 1, 2018, including our Outlook for first quarter 2018 and full year 2018 herein. See "Sustaining capital expenditures" and "Integration capital expenditures" within "Non-GAAP Financial Measures, Segment Measures and Other Calculations" for further information.

---

(a)	See "Non-GAAP Financial Measures, Segment Measures and Other Calculations" herein for a discussion of our definition of Adjusted EBITDA.

(b)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

(a)

Previously issued fourth quarter 2017, full year 2017 and full year 2018 Outlook assumes diluted common shares outstanding as of September 30, 2017 of approximately 408.0 million, 383.4 million and 408.0 million, respectively. For all periods presented, the diluted weighted-average common shares outstanding does not include any assumed conversion of the 6.875% Mandatory Convertible Preferred Stock in the share count.

(b)	See "Non-GAAP Financial Measures, Segment Measures and Other Calculations" herein for a discussion for our definitions of FFO and AFFO.

(c)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

(d)	Attributable to CCIC common stockholders.

---

(a)	Additional information regarding Crown Castle's site rental revenues, including projected revenue from customer licenses, tenant non-renewals, straight-lined revenues and prepaid rent is available in Crown Castle's quarterly Supplemental Information Package posted in the Investors section of its website.

(b)	Includes revenues from amortization of prepaid rent in accordance with GAAP.

(c)	Includes revenues from the construction of new small cell nodes, exclusive of straight-lined revenues related to fixed escalators.

(d)	See "Non-GAAP Financial Measures, Segment Measures and Other Calculations" herein.

(e)	The financial impact of acquisitions, as measured by the initial contribution, and tower builds is excluded from Organic Contribution to Site Rental Revenues until the one-year anniversary of the acquisition or build.

(f)	Calculated as the percentage change from prior year site rental revenues, exclusive of straight-lined revenues associated with fixed escalations, compared to Organic Contribution to Site Rental Revenues for the current period.

---

(a)	Additional information regarding Crown Castle's site rental revenues, including projected revenue from customer licenses, tenant non-renewals, straight-lined revenues and prepaid rent is available in Crown Castle's quarterly Supplemental Information Package posted in the Investors section of its website.

(b)	Includes revenues from amortization of prepaid rent in accordance with GAAP.

(c)	Includes revenues from the construction of new small cell nodes, exclusive of straight-lined revenues related to fixed escalators.

(d)	See "Non-GAAP Financial Measures, Segment Measures and Other Calculations" herein.

(e)	The financial impact of acquisitions, as measured by the initial contribution, and tower builds is excluded from Organic Contribution to Site Rental Revenues until the one-year anniversary of the acquisition or build.

(f)	Calculated based on midpoint of Full Year 2018 Outlook.

(g)	Calculated as the percentage change from prior year site rental revenues, exclusive of straight-lined revenues associated with fixed escalations, compared to Organic Contribution to Site Rental Revenues for the current period.

---

(a)

The Senior Secured Tower Revenue Notes, Series 2010-3 and 2010-6 have anticipated repayment dates in 2020. The Senior Secured Tower Revenue Notes, Series 2015-1 and 2015-2 have anticipated repayment dates in 2022 and 2025, respectively. In January 2018, the Company issued $750.0 million aggregate principal amount of 3.150% senior unsecured notes due July 2023 and $1.0 billion aggregate principal amount of 3.800% senior unsecured notes due February 2028 and used the net proceeds of such offering to repay (1) in full the Senior Secured Tower Revenue Notes, Series 2010-3 and (2) a portion of the outstanding borrowings under the 2016 Revolver.

(b)	The Senior Secured Notes, Series 2009-1, Class A-1 principal amortizes during the period beginning in January 2010 and ending in 2019 and the Senior Secured Notes, 2009-1, Class A-2 principal amortizes during the period beginning in 2019 and ending in 2029.

(c)	Excludes restricted cash.

---

(a)	Excludes restricted cash.

(b)	The Net Debt to Last Quarter Annualized Adjusted EBITDA calculation does not give effect to a full quarter ownership of Lightower, as this acquisition closed on November 1, 2017. For the quarter ended December 31, 2017, Lightower contribution to the Company's Adjusted EBITDA was $83 million.

---

•

Our business depends on the demand for our communications infrastructure, driven primarily by demand for wireless connectivity, and we may be adversely affected by any slowdown in such demand. Additionally, a reduction in the amount or change in the mix of carrier network investment may materially and adversely affect our business (including reducing demand for tenant additions and network services).

•	A substantial portion of our revenues is derived from a small number of customers, and the loss, consolidation or financial instability of any of our limited number of customers may materially decrease revenues or reduce demand for our communications infrastructure and network services.

•	The business model for small cells contains certain differences from our traditional site rental business, resulting in different operational risks. If we do not successfully operate that business model or identify or manage those operational risks, such operations may produce results that are less than anticipated.

•	Our substantial level of indebtedness could adversely affect our ability to react to changes in our business, and the terms of our debt instruments limit our ability to take a number of actions that our management might otherwise believe to be in our best interests. In addition, if we fail to comply with our covenants, our debt could be accelerated.

•	We have a substantial amount of indebtedness. In the event we do not repay or refinance such indebtedness, we could face substantial liquidity issues and might be required to issue equity securities or securities convertible into equity securities, or sell some of our assets to meet our debt payment obligations.

•	Sales or issuances of a substantial number of shares of our common stock may adversely affect the market price of our common stock.

•	As a result of competition in our industry, we may find it more difficult to achieve favorable rental rates on our new or renewing tenant leases.

•	New technologies may reduce demand for our communications infrastructure or negatively impact our revenues.

•	The expansion or development of our business, including through acquisitions, increased product offerings or other strategic growth opportunities, may cause disruptions in our business, which may have an adverse effect on our business, operations or financial results.

•	We may fail to realize all of the anticipated benefits of the Lightower acquisition or those benefits may take longer to realize than expected. We may also encounter significant difficulties in integrating Lightower’s business.

•	If we fail to retain rights to our communications infrastructure, including the land interests under our towers, our business may be adversely affected.

•	Our network services business has historically experienced significant volatility in demand, which reduces the predictability of our results.

•	New wireless technologies may not deploy or be adopted by customers as rapidly or in the manner projected.

---

•	If we fail to comply with laws or regulations which regulate our business and which may change at any time, we may be fined or even lose our right to conduct some of our business.

•	If radio frequency emissions from wireless handsets or equipment on our communications infrastructure are demonstrated to cause negative health effects, potential future claims could adversely affect our operations, costs or revenues.

•	Certain provisions of our restated certificate of incorporation, amended and restated by-laws and operative agreements, and domestic and international competition laws may make it more difficult for a third party to acquire control of us or for us to acquire control of a third party, even if such a change in control would be beneficial to our stockholders.

•	We may be vulnerable to security breaches that could adversely affect our business, operations, and reputation.

•

Future dividend payments to our stockholders will reduce the availability of our cash on hand available to fund future discretionary investments, and may result in a need to incur indebtedness or issue equity securities to fund growth opportunities. In such event, the then current economic, credit market or equity market conditions will impact the availability or cost of such financing, which may hinder our ability to grow our per share results of operations.

•	Remaining qualified to be taxed as a REIT involves highly technical and complex provisions of the U.S. Internal Revenue Code. Failure to remain qualified as a REIT would result in our inability to deduct dividends to stockholders when computing our taxable income, which would reduce our available cash.

•	Complying with REIT requirements, including the 90% distribution requirement, may limit our flexibility or cause us to forgo otherwise attractive opportunities, including certain discretionary investments and potential financing alternatives.

•	REIT related ownership limitations and transfer restrictions may prevent or restrict certain transfers of our capital stock.

•	If we fail to pay scheduled dividends on the 6.875% Mandatory Convertible Preferred Stock, in cash, common stock, or any combination of cash and common stock, we will be prohibited from paying dividends on our common stock, which may jeopardize our status as a REIT.

---

---

---

---

(a)

Segment cost of operations excludes (1) stock-based compensation expense of $7.7 million and $4.5 million for the three months ended December 31, 2017 and 2016, respectively and (2) prepaid lease purchase price adjustments of $5.0 million and $5.3 million for the three months ended December 31, 2017 and 2016, respectively. Segment general and administrative expenses exclude stock-based compensation expense of $22.3 million and $16.8 million for the three months ended December 31, 2017 and 2016, respectively.

(c)	See condensed consolidated statement of operations for further information.

---

(a)

Segment cost of operations excludes (1) stock-based compensation expense of $19.9 million and $22.1 million for the twelve months ended December 31, 2017 and 2016, respectively and (2) prepaid lease purchase price adjustments of $20.1 million and $21.3 million for the twelve months ended December 31, 2017 and 2016, respectively. Segment general and administrative expenses exclude stock-based compensation expense of $76.5 million and $74.5 million for the twelve months ended December 31, 2017 and 2016, respectively.

(c)	See condensed consolidated statement of operations for further information.

---

---

•

Grow cash flows from our communications infrastructure. We seek to maximize our site rental cash flows by working with our customers to provide them quick access to our communications infrastructure and entering into associated long-term contracts. Customer additions or modifications of existing customer equipment (collectively, "customer additions") enable our customers to expand coverage and capacity in order to meet increasing demand for data connectivity, while generating high incremental returns for our business. We believe our product offerings of towers, small cells and fiber solutions provide a comprehensive solution to our customers' growing connectivity needs through our shared communications infrastructure model, which is an efficient and cost effective way to serve our customers. We also believe that there will be considerable future demand for our communications infrastructure based on the location of our communications infrastructure and the rapid growth in demand for data.

•

Return cash provided by operating activities to stockholders in the form of dividends. We believe that distributing a meaningful portion of our cash provided by operating activities appropriately provides stockholders with increased certainty for a portion of expected long-term stockholder value while still retaining sufficient flexibility to invest in our business and deliver growth. We believe this decision reflects the translation of the high-quality, long-term contractual cash flows of our business into stable capital returns to stockholders.

•	Invest capital efficiently to grow cash flows and long-term dividends per share. We seek to invest our available capital, including the net cash provided by our operating activities and external financing sources, in a manner that will increase long-term stockholder value on a risk-adjusted basis. Our historical investments have included the following (in no particular order):

◦	purchases of shares of our common stock from time to time;

◦	acquisitions or construction of towers, fiber and small cells;

◦	acquisitions of land interests under towers;

◦	improvements and structural enhancements to our existing communications infrastructure; or

◦	purchases, repayment or redemption of our debt.

---

(1)	See reconciliations and definitions provided herein. Our AFFO for historical periods may not be comparable to those periods presented prospectively from and after January 1, 2018, including our first quarter 2018 and full year 2018 Outlook included herein. See also "Definitions of Non-GAAP Financial Measures, Segment Measures and Other Calculations" in the Appendix for further information.

(2)	Attributable to CCIC common stockholders.

(3)	Full year 2017 AFFO per share was impacted by (a) two months of contribution from the Lightower acquisition, which closed on November 1, 2017 and (b) the associated pre-funding of the Lightower acquisition through (1) our July 2017 common stock offering, (2) our July 2017 preferred stock offering, and (3) our August 2017 senior unsecured notes offering.

(4)	AFFO per share represents the midpoint of the full year 2018 Outlook as issued on January 24, 2018.

---

(1)	Nominating & Corporate Governance Committee

---

(1)	Based on the sales price, adjusted for common stock dividends, as reported by Bloomberg.

(2)	Based on the period end closing price, adjusted for common stock dividends, as reported by Bloomberg.

(3)	Period end market value of outstanding common shares is calculated as the product of (a) shares of common stock outstanding at period end and (b) closing share price at period end, adjusted for common stock dividends, as reported by Bloomberg.

---

(1)	Excludes small cells and third-party land interests.

(2)	Excludes renewal terms at customers' option.

(3)	Excludes renewal terms at customers' option, weighted by site rental revenues.

(4)	Includes renewal terms at the Company's option, weighted by Towers segment site rental gross margin.

(5)	Based on diluted weighted-average common shares outstanding of 408.1 million, 352.9 million, 383.2 and 340.9 million for the three months ended December 31, 2017 and 2016 and the twelve months ended December 31, 2017 and 2016, respectively.

(6)	See reconciliations of Non-GAAP financial measures provided herein. See also "Definitions of Non-GAAP Measures, Segment Measures and Other Calculations" in the Appendix for a discussion of our definitions of Adjusted EBITDA, FFO and AFFO.

(7)	Attributable to CCIC common stockholders.

---

(1)	Includes net cash used for acquisitions of approximately $7.1 billion and $12 million for the three months ended December 31, 2017 and 2016, respectively, and $9.3 billion and $557 million for the twelve months ended December 31, 2017 and 2016, respectively.

(2)	Balances reflect debt issuance costs as a direct reduction from the respective carrying amounts of debt, with the exception of debt issuance costs associated with the Company's revolving credit facilities.

(3)	The Net Debt to Last Quarter Annualized Adjusted EBITDA calculation does not give effect to a full quarter ownership of Lightower, as this acquisition closed on November 1, 2017. For the quarter ended December 31, 2017, Lightower contribution to the Company's Adjusted EBITDA was $83 million.

(4)	Exclusive of depreciation, amortization and accretion.

(5)	The assumption for first quarter 2018 and full year 2018 diluted weighted-average common shares outstanding is 408.1 million based on diluted common shares outstanding as of December 31, 2017. For all periods presented, the diluted weighted-average common shares outstanding does not include any assumed conversion of the 6.875% Mandatory Convertible Preferred Stock in the share count.

(6)	Calculated using net income (loss) attributable to CCIC common stockholders.

(7)

See reconciliation of this non-GAAP financial measure to net income (loss) and definition included herein. Our AFFO for historical periods may not be comparable to those periods presented prospectively from and after January 1, 2018, including our first quarter 2018 and full year 2018 Outlook included herein. See also "Definitions of Non-GAAP Financial Measures, Segment Measures and Other Calculations" in the Appendix for further information.

(8)	See the reconciliation of "components of interest expense and amortization of deferred financing costs" in the Appendix.

(9)	Attributable to CCIC common stockholders.

---

(1)	See additional information regarding Crown Castle's site rental revenues including projected revenue from customer licenses, tenant non-renewals, straight-lined revenues and prepaid rent herein.

(2)	Includes revenues from amortization of prepaid rent in accordance with GAAP.

(3)	Includes revenues from the construction of new small cell nodes, exclusive of straight-lined revenues related to fixed escalators.

(4)	See definitions provided herein.

(5)	The financial impact of acquisitions, as measured by the initial contribution, and tower builds is excluded from Organic Contribution to Site Rental Revenues until the one-year anniversary of the acquisition or build.

(6)	Calculated based on midpoint of Full Year 2018 Outlook.

(7)	Calculated as the percentage change from prior year site rental revenues, exclusive of straight-lined revenues associated with fixed escalations, compared to Organic Contribution to Site Rental Revenues for the current period.

---

---

---

(1)

Segment cost of operations excludes (1) stock-based compensation expense of $7.7 million and $4.5 million for the three months ended December 31, 2017 and 2016, respectively and (2) prepaid lease purchase price adjustments of $5.0 million and $5.3 million for the three months ended December 31, 2017 and 2016, respectively. Segment general and administrative expenses exclude stock-based compensation expense of $22.3 million and $16.8 million for the three months ended December 31, 2017 and 2016, respectively.

(2)	See "Definitions of Non-GAAP Financial Measures, Segment Measures and Other Calculations" in the Appendix for a discussion of our definitions of segment site rental gross margin, segment network services and other gross margin and segment operating profit.

(3)	See condensed consolidated statement of operations for further information.

---

(1)

Segment cost of operations excludes (1) stock-based compensation expense of $19.9 million and $22.1 million for the twelve months ended December 31, 2017 and 2016, respectively and (2) prepaid lease purchase price adjustments of $20.1 million and $21.3 million for the twelve months ended December 31, 2017 and 2016, respectively. Segment general and administrative expenses exclude stock-based compensation expense of $76.5 million and $74.5 million for the twelve months ended December 31, 2017 and 2016, respectively.

(2)	See "Definitions of Non-GAAP Financial Measures, Segment Measures and Other Calculations" in the Appendix for a discussion of our definitions of segment site rental gross margin, segment network services and other gross margin and segment operating profit.

(3)	See condensed consolidated statement of operations for further information.

---

(1)	See "Definitions of Non-GAAP Measures, Segment Measures and Other Calculations" in the Appendix for a discussion of our definitions of FFO and AFFO.

(2)	FFO and AFFO are reduced by cash paid for preferred stock dividends during the period in which they are paid.

(3)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

(4)	Attributable to CCIC common stockholders.

(5)	Based on the diluted weighted-average common shares outstanding for the three and twelve months ended December 31, 2017 and 2016. For all periods presented, the diluted weighted-average common shares outstanding does not include any assumed conversion of the 6.875% Mandatory Convertible Preferred Stock in the share count.

---

---

(1)	See additional information regarding Crown Castle's site rental revenues including projected revenue from customer licenses, tenant non-renewals, straight-lined revenues and prepaid rent herein.

(2)	Includes revenues from amortization of prepaid rent in accordance with GAAP.

(3)	Includes revenues from the construction of new small cell nodes, exclusive of straight-lined revenues related to fixed escalators.

(4)	See definitions provided herein.

(5)	The financial impact of acquisitions, as measured by the initial contribution, and tower builds is excluded from Organic Contribution to Site Rental Revenues until the one-year anniversary of the acquisition or build.

(6)	Calculated as the percentage change from prior year site rental revenues, exclusive of straight-lined revenues associated with fixed escalations, compared to Organic Contribution to Site Rental Revenues for the current period.

---

(1)	In accordance with GAAP accounting, if payment terms call for fixed escalations, or rent free periods, the revenue is recognized on a straight-line basis over the fixed, non-cancelable term of the contract. Since the Company recognizes revenue on a straight-line basis, a portion of the site rental revenue in a given period represents cash collected or contractually collectible in other periods.

(2)	Reflects up front payments received from long-term tenant contracts and other deferred credits (commonly referred to as prepaid rent), and the amortization thereof for GAAP revenue recognition purposes.

---

(1)	Based on customer licenses as of December 31, 2017. All customer licenses are assumed to renew for a new term at current term end date. CPI-linked customer contracts are assumed to escalate at 3% per annum.

(2)	Based on existing ground leases as of December 31, 2017. CPI-linked leases are assumed to escalate at 3% per annum.

---

(1)	Reflects lease renewals by year by customer; dollar amounts represent annualized cash site rental revenues from assumed renewals or extension as reflected in the table "Projected Revenue from Customer Contracts."

(2)	Weighted by site rental revenue contributions; excludes renewals at the customers' option.

---

(1)	Yield is calculated as LQA Towers segment site rental gross margin divided by invested capital.

(2)	Reflects gross total assets, including incremental capital invested by the Company since time of acquisition or construction completion. Inclusive of invested capital related to land at the tower site.

---

(1)	Includes towers and rooftops, excludes small cells and third-party land interests.

---

(1)	Includes towers and rooftops, excludes small cells and third-party land interests.

---

(1)	Includes towers and rooftops, excludes small cells and third-party land interests.

(2)	Includes renewal terms at the Company’s option; weighted by Towers segment site rental gross margin.

(1)	Includes the impact from the amortization of lump sum payments.

---

(1)	Represents the weighted-average stated interest rate.

(2)	Represents the applicable amount of debt divided by LQA consolidated Adjusted EBITDA. The Net Debt to Last Quarter Annualized Adjusted EBITDA calculation does not give effect to a full quarter ownership of Lightower, as this acquisition closed on November 1, 2017. For the quarter ended December 31, 2017, Lightower contribution to the Company's Adjusted EBITDA was $83 million.

(3)

If the respective series of such debt is not paid in full on or prior to an applicable date then the Excess Cash Flow (as defined in the indenture) of the issuers of such notes will be used to repay principal of the applicable series, and additional interest (of an additional approximately 5% per annum) will accrue on the respective series. The Senior Secured Tower Revenue Notes, Series 2010-3 and 2010-6 have anticipated repayment dates in 2020. The Senior Secured Tower Revenue Notes, Series 2015-1 and 2015-2 have anticipated repayment dates of 2022 and 2025, respectively. Notes are prepayable at par if voluntarily repaid six months or less prior to maturity; earlier prepayment may require additional consideration. In January 2018, the Company issued $750.0 million aggregate principal amount of 3.150% senior unsecured notes due July 2023 and $1.0 billion aggregate principal amount of 3.800% senior unsecured notes due February 2028 and used the net proceeds of such offering to repay (a) in full the Senior Secured Tower Revenue Notes, Series 2010-3 and (b) a portion of the outstanding borrowings under the 2016 Revolver.

(4)	As of December 31, 2017, the undrawn availability under the $3.5 billion Revolving Credit Facility is $2.5 billion.

(5)	Market capitalization calculated based on $111.01 closing price and 406 million shares outstanding as of December 31, 2017.

(6)	Represents the sum of net debt, preferred stock (at liquidation value) and market capitalization.

---

(1)	Where applicable, maturities reflect the Anticipated Repayment Date as defined in the respective debt agreement; excludes capital leases and other obligations; amounts presented at face value net of repurchases held at CCIC.

(2)	The debt maturity overview does not reflect the Company's January 2018 senior unsecured notes offering and the use of proceeds from such offering, including the repayment in full of the Senior Secured Tower Revenue Notes, Series 2010-3, which had an Anticipated Repayment Date in 2020.

---

(1)	We have an At-The-Market stock offering program ("ATM Program") through which we may, from time to time, issue and sell shares of our common stock having an aggregate cumulative gross sales price of up to $500.0 million to or through sales agents. As of December 31, 2017, 4.1 million shares of common stock had been sold under the ATM Program generating net proceeds of $346.3 million.

(2)	Exclusive of restricted cash.

(3)	Availability at any point in time is subject to reaffirmation of the representations and warranties in, and there being no default under, our credit agreement governing our Senior Unsecured Credit Facility.

(4)	Does not give effect to our January 2018 issuance of $750.0 million aggregate principal amount of 3.150% senior unsecured notes due July 2023 and $1.0 billion aggregate principal amount of 3.800% senior unsecured notes due February 2028, and the associated use of proceeds.

(5)	Balances reflect debt issuance costs as a direct reduction from the respective carrying amounts of debt, with the exception of debt issuance costs associated with the Company's revolving credit facilities.

---

(1)	As defined in the respective debt agreement. In the indentures for the 2010 Tower Revenue Notes, 2015 Tower Revenue Notes and the 2009 Securitized Notes, the defined term for Debt Service Coverage Ratio is "DSCR".

(2)	Failure to comply with the financial maintenance covenants would, absent a waiver, result in an event of default under the credit agreement governing our 2016 Credit Facility.

(3)	Applicable solely to the extent that the senior unsecured debt rating by any two of S&P, Moody's and Fitch is lower than BBB-, Baa3 or BBB-, respectively. If applicable, the consolidated interest coverage ratio must be greater than or equal to 2.50.

(4)

The 2010 Tower Revenue Notes, 2015 Tower Revenue Notes, and 2009 Securitized Notes also include the potential for amortization events, which could result in applying current and future cash flow to the prepayment of debt with applicable prepayment consideration. An amortization event occurs when the Debt Service Coverage Ratio falls below 1.45x, 1.45x or 1.15x, in each case as described under the indentures for the 2010 Tower Revenue Notes, 2015 Tower Revenue Notes, or 2009 Securitized Notes, respectively.

(5)	Rating Agency Confirmation (as defined in the respective debt agreement) is also required.

(6)	Does not give effect to our January 2018 issuance of $750.0 million aggregate principal amount of 3.150% senior unsecured notes due July 2023 and $1.0 billion aggregate principal amount of 3.800% senior unsecured notes due February 2028, and the associated use of proceeds.

---

(1)	Excludes capital lease and other obligations.

(2)	Face value net of required amortizations; assumes no maturity or balloon principal payments; excludes capital leases.

(3)	Interest expense calculated based on current interest rates.

(4)	Interest expense calculated based on current interest rates until the sooner of the (1) stated maturity date or (2) the Anticipated Repayment Date, at which time the face value amount outstanding of such indebtedness is refinanced at current rates plus 12.5 bps.

(5)	Interest expense calculated based on current interest rates. Forward LIBOR assumptions are derived from the 1-month LIBOR forward curve as of December 31, 2017. Calculation assumes no changes to future interest rate margin spread over LIBOR due to changes in the Borrower’s senior unsecured credit rating.

(6)	Interest expense calculated based on current interest rates using the 1-month LIBOR forward curve as of December 31, 2017 plus 12.5 bps.

(7)	Does not give effect to our January 2018 issuance of $750.0 million aggregate principal amount of 3.150% senior unsecured notes due July 2023 and $1.0 billion aggregate principal amount of 3.800% senior unsecured notes due February 2028, and the associated use of proceeds.

---

•

Adjusted EBITDA is useful to investors or other interested parties in evaluating our financial performance. Adjusted EBITDA is the primary measure used by management (1) to evaluate the economic productivity of our operations and (2) for purposes of making decisions about allocating resources to, and assessing the performance of, our operations. Management believes that Adjusted EBITDA helps investors or other interested parties meaningfully evaluate and compare the results of our operations (1) from period to period and (2) to our competitors, by removing the impact of our capital structure (primarily interest charges from our outstanding debt) and asset base (primarily depreciation, amortization and accretion) from our financial results. Management also believes Adjusted EBITDA is frequently used by investors or other interested parties in the evaluation of the communications infrastructure sector and other REITs to measure financial performance without regard to items such as depreciation, amortization and accretion, which can vary depending upon accounting methods and the book value of assets. In addition, Adjusted EBITDA is similar to the measure of current financial performance generally used in our debt covenant calculations. Adjusted EBITDA should be considered only as a supplement to net income computed in accordance with GAAP as a measure of our performance.

•

AFFO and AFFO per share are useful to investors or other interested parties in evaluating our financial performance. Management believes that AFFO and AFFO per share help investors or other interested parties meaningfully evaluate our financial performance as they include (1) the impact of our capital structure (primarily interest expense on our outstanding debt and dividends on our preferred stock) and (2) sustaining capital expenditures and excludes the impact of our (a) asset base (primarily depreciation, amortization and accretion) and (b) certain non-cash items, including straight-lined revenues and expenses related to fixed escalations and rent free periods. GAAP requires rental revenues and expenses related to leases that contain specified rental increases over the life of the lease to be recognized evenly over the life of the lease. In accordance with GAAP, if payment terms call for fixed escalations, or rent free periods, the revenue or expense is recognized on a straight-lined basis over the fixed, non-cancelable term of the contract. Management notes that the Company uses AFFO and AFFO per share only as a performance measure. AFFO and AFFO per share should be considered only as a supplement to net income computed in accordance with GAAP as a measure of our performance and should not be considered as an alternative to cash flows from operations or as residual cash flow available for discretionary investment.

•

FFO and FFO per share are useful to investors or other interested parties in evaluating our financial performance. Management believes that FFO may be used by investors or other interested parties as a basis to compare our financial performance with that of other REITs. FFO and FFO per share help investors or other interested parties meaningfully evaluate financial performance by excluding the impact of our asset base (primarily depreciation, amortization and accretion). FFO and FFO per share are not key performance indicators used by the Company. FFO and FFO per share should be considered only as a supplement to net income computed in accordance with GAAP as a measure of our performance and should not be considered as an alternative to cash flow from operations.

---

•

Organic Contribution to Site Rental Revenues is useful to investors or other interested parties in understanding the components of the year-over-year changes in our site rental revenues computed in accordance with GAAP. Management uses the Organic Contribution to Site Rental Revenues to assess year-over-year growth rates for our rental activities, to evaluate current performance, to capture trends in rental rates, new leasing activities and customer non-renewals in our core business, as well to forecast future results. Organic Contribution to Site Rental Revenues is not meant as an alternative measure of revenue and should be considered only as a supplement in understanding and assessing the performance of our site rental revenues computed in accordance with GAAP.

---

---

(1)	See the reconciliation of "components of historical interest expense and amortization of deferred financing costs" herein.

(2)	See "Definitions of Non-GAAP Measures, Segment Measures and Other Calculations" herein for a discussion of our definition of Adjusted EBITDA.

(3)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

---

(1)	See the reconciliation of "components of current outlook for interest expense and amortization of deferred financing costs" herein.

(2)	See "Definitions of Non-GAAP Measures, Segment Measures and Other Calculations" herein for a discussion of our definition of Adjusted EBITDA.

(3)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

---

(1)	See “Definitions of Non-GAAP Financial Measures, Segment Measures and Other Calculations” herein for a discussion of our definitions of FFO and AFFO.

(2)	FFO and AFFO are reduced by cash paid for preferred stock dividends during the period in which they are paid.

(3)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

(4)	Attributable to CCIC common stockholders.

(5)	Based on the diluted weighted-average common shares outstanding for the three and twelve months ended December 31, 2017 and 2016. For all periods presented, the diluted weighted-average common shares outstanding does not include any assumed conversion of the 6.875% Mandatory Convertible Preferred Stock in the share count.

---

(1)	See "Definitions of Non-GAAP Measures, Segment Measures and Other Calculations" herein for a discussion of our definitions of FFO and AFFO.

(2)	FFO and AFFO are reduced by cash paid for preferred stock dividends during the period in which they are paid.

(3)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

(4)	Attributable to CCIC common stockholders.

(5)	Adjusts the income tax provision to reflect our estimate of the cash taxes paid had we been a REIT for all periods presented, and is primarily comprised of foreign taxes. As a result income tax expense (benefit) is lower by the amount of the adjustment.

(6)	Based on the diluted weighted-average common shares outstanding for the twelve months ended December 31, 2016, 2015, 2014 and 2013.

---

(1)

See “Definitions of Non-GAAP Financial Measures, Segment Measures and Other Calculations” herein for a discussion of our definitions of FFO and AFFO. Our AFFO for historical periods may not be comparable to those periods presented prospectively from and after January 1, 2018, including our first quarter 2018 and full year 2018 Outlook included herein. See also "Definitions of Non-GAAP Financial Measures, Segment Measures and Other Calculations" in the Appendix for further information.

(2)	The above reconciliation excludes line items included in our definition which are not applicable for the periods shown.

(3)	Attributable to CCIC common stockholders.

(4)	The assumption for first quarter 2018 and full year 2018 diluted weighted-average common shares outstanding is 408.1 million based on diluted common shares outstanding as of December 31, 2017. For all periods presented, the diluted weighted-average common shares outstanding does not include any assumed conversion of the 6.875% Mandatory Convertible Preferred Stock in the share count.

---

(1)	Excludes restricted cash.

(2)	The Net Debt to Last Quarter Annualized Adjusted EBITDA calculation does not give effect to a full quarter ownership of Lightower, as this acquisition closed on November 1, 2017. For the quarter ended December 31, 2017, Lightower contribution to the Company's Adjusted EBITDA was $83 million.