Incentive Plan

12 Months Ended

Dec. 31, 2013

Incentive Plan

13. Incentive Plan

Our Amended and Restated 2004 Incentive Award Plan (as defined below) provides for the grant of incentive awards to employees, directors and consultants. Awards issuable under the Amended and Restated 2004 Incentive Award Plan include stock options, restricted stock, dividend equivalents, stock appreciation rights, long-term incentive units, cash performance bonuses and other incentive awards. Only employees are eligible to receive incentive stock options under the Amended and Restated 2004 Incentive Award Plan. Initially, we had reserved a total of 4,474,102 shares of common stock for issuance pursuant to the 2004 Incentive Award Plan, subject to certain adjustments set forth in the 2004 Incentive Award Plan. On May 2, 2007, Digital Realty Trust, Inc.’s stockholders approved the First Amended and Restated Digital Realty Trust, Inc., Digital Services, Inc. and Digital Realty Trust, L.P. 2004 Incentive Award Plan (as amended, the Amended and Restated 2004 Incentive Award Plan). The Amended and Restated 2004 Incentive Award Plan increases the aggregate number of shares of stock which may be issued or transferred under the plan by 5,000,000 shares to a total of 9,474,102 shares, and provides that the maximum number of shares of stock with respect to awards granted to any one participant during a calendar year will be 1,500,000 and the maximum amount that may be paid in cash during any calendar year with respect to any performance-based award not denominated in stock or otherwise for which the foregoing limitation would not be an effective limitation for purposes of Section 162(m) of the Code will be $10.0 million.

As of December 31, 2013, 3,209,240 shares of common stock or awards convertible into or exchangeable for common stock remained available for future issuance under the Amended and Restated 2004 Incentive Award Plan. Each long-term incentive unit and Class C Unit issued under the Amended and Restated 2004 Incentive Award Plan will count as one share of common stock for purposes of calculating the limit on shares that may be issued under the Amended and Restated 2004 Incentive Award Plan and the individual award limit discussed above.

(a) Long-Term Incentive Units

Long-term incentive units, which are also referred to as profits interest units, may be issued to eligible participants for the performance of services to or for the benefit of the Operating Partnership. Long-term incentive units, whether vested or not, will receive the same quarterly per unit distributions as Operating Partnership common units, which equal per share distributions on Digital Realty Trust, Inc. common stock. Initially, long-term incentive units do not have full parity with common units with respect to liquidating distributions. If such parity is reached, vested long-term incentive units may be converted into an equal number of common units of the Operating Partnership at any time, and thereafter enjoy all the rights of common units of the Operating Partnership, including redemption rights.

In order to achieve full parity with common units, long-term incentive units must be fully vested and the holder’s capital account balance in respect of such long-term incentive units must be equal to the capital account balance of a holder of an equivalent number of common units. The capital account balance attributable to each common unit is generally expected to be the same, in part because of the amount credited to a partner’s capital account upon the partner’s contribution of property to the Operating Partnership, and in part because the partnership agreement provides, in most cases, that allocations of income, gain, loss and deduction (which will adjust the partner’s capital accounts) are to be made to the common units on a proportionate basis. As a result, with respect to a number of long-term incentive units, it is possible to determine the capital account balance of an equivalent number of common units by multiplying the number of long-term incentive units by the capital account balance with respect to a common unit.

A partner’s initial capital account balance is equal to the amount the partner paid (or contributed to the Operating Partnership) for the partner’s units and is subject to subsequent adjustments, including with respect to the partner’s share of income, gain or loss of the Operating Partnership. Because a holder of long-term incentive units generally will not pay for the long-term incentive units, the initial capital account balance attributable to such long-term incentive units will be zero. However, the Operating Partnership is required to allocate income, gain, loss and deduction to the partner’s capital accounts in accordance with the terms of the partnership agreement, subject to applicable Treasury Regulations. The partnership agreement provides that holders of long-term incentive units will receive special allocations of gain in the event of a sale or “hypothetical sale” of assets of the Operating Partnership prior to the allocation of gain to Digital Realty Trust, Inc. or other limited partners with respect to their common units. The amount of such allocation will, to the extent of any such gain, be equal to the difference between the capital account balance of a holder of long-term incentive units attributable to such units and the capital account balance attributable to an equivalent number of common units. If and when such gain allocation is fully made, a holder of long-term incentive units will have achieved full parity with holders of common units. To the extent that, upon an actual sale or a “hypothetical sale” of the Operating Partnership’s assets as described above, there is not sufficient gain to allocate to a holder’s capital account with respect to long-term incentive units, or if such sale or “hypothetical sale” does not occur, such units will not achieve parity with common units.

The term “hypothetical sale” refers to circumstances that are not actual sales of the Operating Partnership’s assets but that require certain adjustments to the value of the Operating Partnership’s assets and the partners’ capital account balances. Specifically, the partnership agreement provides that, from time to time, in accordance with applicable Treasury Regulations, the Operating Partnership will adjust the value of its assets to equal their respective fair market values, and adjust the partners’ capital accounts, in accordance with the terms of the partnership agreement, as if the Operating Partnership sold its assets for an amount equal to their value. Times for making such adjustments generally include the liquidation of the Operating Partnership, the acquisition of an additional interest in the Operating Partnership by a new or existing partner in exchange for more than a de minimis capital contribution, the distribution by the Operating Partnership to a partner of more than a de minimis amount of partnership property as consideration for an interest in the Operating Partnership, in connection with the grant of an interest in the Operating Partnership (other than a de minimis interest) as consideration for the performance of services to or for the benefit of the Operating Partnership (including the grant of a long-term incentive unit), and at such other times as may be desirable or required to comply with the Treasury Regulations.

During the years ended December 31, 2013, 2012 and 2011, certain employees and directors were granted an aggregate of 89,769,79,237 and 85,910 long-term incentive units, respectively. During the years ended December 31, 2013, 2012 and 2011, certain employees were also granted an aggregate of 95,316,86,843 and 98,632 long-term incentive units, respectively, which, in addition to a service condition, are subject to a performance condition that impacts the number of units which ultimately vests. The performance condition is based upon our achievement of the respective fiscal years’ Core Funds From Operations, or CFFO, per share targets. Upon evaluating the results of the performance condition, the final number of units is determined and such units vest based on satisfaction of the service conditions. The service conditions of the awards provide for 20% vesting on each of the first and second anniversaries of the grant date and 30% vesting on each of the third and fourth anniversaries of the grant date, provided the grantee continues employment on each anniversary date. Based on our 2013, 2012 and 2011 CFFO per diluted share and unit, 75,105of the 2013 long-term incentive units, net of forfeitures and 78,118 of the 2012 long-term incentive units, net of forfeitures, respectively, and all of the 2011 long-term incentive units, respectively, satisfied the performance condition. The grant date fair values, which equal the market price of Digital Realty Trust, Inc. common stock, are being expensed on a straight-line basis for service awards over four years, the current vesting period of the long-term incentive units. For performance based awards, we expense the fair value using an accelerated method with each vesting tranche valued as a separate award.  

The expense recorded for the years ended December 31, 2013, 2012 and 2011 related to long-term incentive units was approximately $8.9 million, $9.0 million and $8.7 million, respectively. We capitalized amounts relating to compensation expense of employees direct and incremental to construction and successful leasing activities of approximately $1.6 million, $1.1 million and $0.8 million for the years ended December 31, 2013, 2012 and 2011, respectively. Unearned compensation representing the unvested portion of the long-term incentive units totaled $12.9 million and $13.3 million as of December 31, 2013 and 2012, respectively. We expect to recognize this unearned compensation over the next 2.5 years on a weighted average basis.

(b) Class C Profits Interest Units

On May 2, 2007, we granted awards of Class C Profits Interest Units of the Operating Partnership or similar stock-based performance awards, which we refer to collectively as the Class C Units, under the Amended and Restated 2004 Incentive Award Plan (2007 Grant) to each of our named executive officers and certain other officers and employees.

The Class C Units subject to this award were subject to vesting based on the achievement of a total stockholder return (which we refer to as the market condition) as measured on November 1, 2008 (which we refer to as the first measurement date) and May 1, 2010 (which we refer to as the second measurement date).

We previously determined that the market condition with respect to the first measurement date was not achieved. On May 1, 2010, we determined that 593,316 of the Class C Units and 20,169 shares of restricted stock subject to the 2007 Grant satisfied the market condition on the second measurement date (May 1, 2010), with the value of these units equal to the maximum amount of the award pool payable pursuant to the 2007 Grant on the second measurement date. Of the Class C Units that satisfied the market condition on May 1, 2010, 60% vested on May 1, 2010 and the remaining 40% vested ratably each month through April 30, 2012.

The fair value of the 2007 Grant was measured on the grant date using a Monte Carlo simulation to estimate the probability of the multiple market conditions being satisfied. The Monte Carlo simulation uses a statistical formula underlying the Black-Scholes and binomial formulas, and such simulation was run approximately 100,000 times. For each simulation, the value of the payoff was calculated at the settlement date and was then discounted to the grant date at a risk-free interest rate. The expected value of the Class C Units on the grant date was determined by multiplying the average of the values over all simulations by the number of outstanding shares of Digital Realty Trust, Inc. common stock and Operating Partnership units. The valuation was performed in a risk-neutral framework, so no assumption was made with respect to an equity risk premium. Other significant assumptions used in the valuation included an expected term of 36 months, expected stock price volatility of 23%, a risk-free interest rate of 4.6%, and a dividend growth rate of 5.0%. The fixed award limit under the plan was $17 million for the first market condition and $40 million for the second market condition, and there were 69.2 million shares of Digital Realty Trust, Inc. common stock and Operating Partnership units outstanding as of the 2007 Grant date. The grant date fair value of these awards of approximately $11.8 million was recognized as compensation expense on a straight-line basis over the expected service period of five years, which ended during the three months ended June 30, 2012.

We recognized compensation expense related to the Class C Units subject to the 2007 Grant of $0.5 million and $2.0 million for the years ended December 31, 2012 and 2011, respectively. We capitalized amounts relating to compensation expense of employees direct and incremental to construction and successful leasing activities of approximately $0.1 million and $0.3 million for the years ended December 31, 2012 and 2011, respectively.

(c) Stock Options

The fair value of each option granted under the Amended and Restated 2004 Incentive Award Plan is estimated on the date of the grant using the Black-Scholes option-pricing model. For the years ended December 31, 2013, 2012 and 2011, no stock options were granted. The fair values are being expensed on a straight-line basis over the vesting period of the options, which ranges from four to five years. All unearned compensation has been recognized as of December 31, 2012.  The expense recorded for the years ended December 31, 2012 and 2011 was approximately $0.2 million and  $0.8 million, respectively. We capitalized amounts relating to compensation expense of employees direct and incremental to construction and successful leasing activities of approximately $0.1 million and  $0.2 million for the years ended December 31, 2012 and 2011, respectively.

The following table summarizes the Amended and Restated 2004 Incentive Award Plan’s stock option activity for the year ended December 31, 2013:

	Year Ended December 31, 2013
	Shares	Weighted average exercise price
Options outstanding, beginning of period	129,259	$              30.61
Exercised	(5,569)	41.24
Cancelled / Forfeited	-	-
Options outstanding, end of period	123,690	$              30.13
Exercisable, end of period	123,690	$              30.13

The following table summarizes information about stock options outstanding and exercisable as of December 31, 2013:

Options outstanding and exercisable
Exercise price	Number outstanding	Weighted average remaining contractual life (years)	Weighted average exercise price	Aggregate intrinsic value
$12.00 - 13.02	34,870	0.82	$          12.00	$      1,294,374
$20.37 - 28.09	17,000	1.89	21.28	473,310
$33.18 - 41.73	71,820	3.29	41.02	581,417
	123,690	2.40	$          30.13	$      2,349,101

(d) Restricted Stock

During the years ended December 31, 2013, 2012 and 2011, certain employees were granted an aggregate of 79,114,  46,617 and 41,220 shares of restricted stock, respectively. During the years ended December 31, 2013, 2012 and 2011, certain employees were also granted an aggregate of 69,995,  52,947and 50,999 shares of restricted stock, respectively, which, in addition to a service condition, are subject to a performance condition that impacts the number of shares which ultimately vests. The performance condition is based upon our achievement of the respective year’s CFFO per share targets. Upon evaluating the results of the performance condition, the final number of shares is determined and such shares vest based on satisfaction of the service conditions. The service conditions of the awards provide for 20% vesting on each of the first and second anniversaries of the grant date and 30% vesting on each of the third and fourth anniversaries of the grant date provided the grantee continues employment on each anniversary date. Based on our 2013, 2012 and 2011 CFFO per diluted share and unit, 50,805 shares of the2013 restricted stock awards (net of forfeitures) and 49,325 shares of the 2012 restricted stock awards (net of forfeitures) and all of the 2011 restricted stock, respectively, satisfied the performance condition.

The grant date fair values, which equal the market price of Digital Realty Trust, Inc. common stock, are being expensed on a straight-line basis for service awards over the vesting period of the restricted stock, which ranges from three to four years. For performance based awards, we expense the fair value using an accelerated method with each vesting tranche valued as a separate award.

The expense recorded for the years ended December 31, 2013, 2012 and 2011 related to grants of restricted stock was approximately $2.7 million, $2.9 million and $2.0 million, respectively. We capitalized amounts relating to compensation expense of employees direct and incremental to construction and successful leasing activities of approximately $2.5 million, $2.1 million and $1.5 million for the years ended December 31, 2013, 2012 and 2011, respectively. Unearned compensation representing the unvested portion of the restricted stock totaled $8.7 million and $7.4 million as of December 31, 2013 and 2012, respectively. We expect to recognize this unearned compensation over the next 2.8 years on a weighted average basis.

(e) 401(k) Plan

We have a 401(k) plan whereby our employees may contribute a portion of their compensation to their respective retirement accounts, in an amount not to exceed the maximum allowed under the Code. The 401(k) Plan complies with Internal Revenue Service requirements as a 401(k) Safe Harbor Plan whereby discretionary contributions made by us are 100% vested. The aggregate cost of our contributions to the 401(k) Plan was approximately $2.4 million, $2.0 million, and $1.5 million for the years ended December 31, 2013, 2012 and 2011, respectively.

Digital Realty Trust, L.P. [Member]

Incentive Plan

13. Incentive Plan

Our Amended and Restated 2004 Incentive Award Plan (as defined below) provides for the grant of incentive awards to employees, directors and consultants. Awards issuable under the Amended and Restated 2004 Incentive Award Plan include stock options, restricted stock, dividend equivalents, stock appreciation rights, long-term incentive units, cash performance bonuses and other incentive awards. Only employees are eligible to receive incentive stock options under the Amended and Restated 2004 Incentive Award Plan. Initially, we had reserved a total of 4,474,102 shares of common stock for issuance pursuant to the 2004 Incentive Award Plan, subject to certain adjustments set forth in the 2004 Incentive Award Plan. On May 2, 2007, Digital Realty Trust, Inc.’s stockholders approved the First Amended and Restated Digital Realty Trust, Inc., Digital Services, Inc. and Digital Realty Trust, L.P. 2004 Incentive Award Plan (as amended, the Amended and Restated 2004 Incentive Award Plan). The Amended and Restated 2004 Incentive Award Plan increases the aggregate number of shares of stock which may be issued or transferred under the plan by 5,000,000 shares to a total of 9,474,102 shares, and provides that the maximum number of shares of stock with respect to awards granted to any one participant during a calendar year will be 1,500,000 and the maximum amount that may be paid in cash during any calendar year with respect to any performance-based award not denominated in stock or otherwise for which the foregoing limitation would not be an effective limitation for purposes of Section 162(m) of the Code will be $10.0 million.

As of December 31, 2013, 3,209,240 shares of common stock or awards convertible into or exchangeable for common stock remained available for future issuance under the Amended and Restated 2004 Incentive Award Plan. Each long-term incentive unit and Class C Unit issued under the Amended and Restated 2004 Incentive Award Plan will count as one share of common stock for purposes of calculating the limit on shares that may be issued under the Amended and Restated 2004 Incentive Award Plan and the individual award limit discussed above.

(a) Long-Term Incentive Units

Long-term incentive units, which are also referred to as profits interest units, may be issued to eligible participants for the performance of services to or for the benefit of the Operating Partnership. Long-term incentive units, whether vested or not, will receive the same quarterly per unit distributions as Operating Partnership common units, which equal per share distributions on Digital Realty Trust, Inc. common stock. Initially, long-term incentive units do not have full parity with common units with respect to liquidating distributions. If such parity is reached, vested long-term incentive units may be converted into an equal number of common units of the Operating Partnership at any time, and thereafter enjoy all the rights of common units of the Operating Partnership, including redemption rights.

In order to achieve full parity with common units, long-term incentive units must be fully vested and the holder’s capital account balance in respect of such long-term incentive units must be equal to the capital account balance of a holder of an equivalent number of common units. The capital account balance attributable to each common unit is generally expected to be the same, in part because of the amount credited to a partner’s capital account upon the partner’s contribution of property to the Operating Partnership, and in part because the partnership agreement provides, in most cases, that allocations of income, gain, loss and deduction (which will adjust the partner’s capital accounts) are to be made to the common units on a proportionate basis. As a result, with respect to a number of long-term incentive units, it is possible to determine the capital account balance of an equivalent number of common units by multiplying the number of long-term incentive units by the capital account balance with respect to a common unit.

A partner’s initial capital account balance is equal to the amount the partner paid (or contributed to the Operating Partnership) for the partner’s units and is subject to subsequent adjustments, including with respect to the partner’s share of income, gain or loss of the Operating Partnership. Because a holder of long-term incentive units generally will not pay for the long-term incentive units, the initial capital account balance attributable to such long-term incentive units will be zero. However, the Operating Partnership is required to allocate income, gain, loss and deduction to the partner’s capital accounts in accordance with the terms of the partnership agreement, subject to applicable Treasury Regulations. The partnership agreement provides that holders of long-term incentive units will receive special allocations of gain in the event of a sale or “hypothetical sale” of assets of the Operating Partnership prior to the allocation of gain to Digital Realty Trust, Inc. or other limited partners with respect to their common units. The amount of such allocation will, to the extent of any such gain, be equal to the difference between the capital account balance of a holder of long-term incentive units attributable to such units and the capital account balance attributable to an equivalent number of common units. If and when such gain allocation is fully made, a holder of long-term incentive units will have achieved full parity with holders of common units. To the extent that, upon an actual sale or a “hypothetical sale” of the Operating Partnership’s assets as described above, there is not sufficient gain to allocate to a holder’s capital account with respect to long-term incentive units, or if such sale or “hypothetical sale” does not occur, such units will not achieve parity with common units.

The term “hypothetical sale” refers to circumstances that are not actual sales of the Operating Partnership’s assets but that require certain adjustments to the value of the Operating Partnership’s assets and the partners’ capital account balances. Specifically, the partnership agreement provides that, from time to time, in accordance with applicable Treasury Regulations, the Operating Partnership will adjust the value of its assets to equal their respective fair market values, and adjust the partners’ capital accounts, in accordance with the terms of the partnership agreement, as if the Operating Partnership sold its assets for an amount equal to their value. Times for making such adjustments generally include the liquidation of the Operating Partnership, the acquisition of an additional interest in the Operating Partnership by a new or existing partner in exchange for more than a de minimis capital contribution, the distribution by the Operating Partnership to a partner of more than a de minimis amount of partnership property as consideration for an interest in the Operating Partnership, in connection with the grant of an interest in the Operating Partnership (other than a de minimis interest) as consideration for the performance of services to or for the benefit of the Operating Partnership (including the grant of a long-term incentive unit), and at such other times as may be desirable or required to comply with the Treasury Regulations.

During the years ended December 31, 2013, 2012 and 2011, certain employees and directors were granted an aggregate of 89,769,79,237 and 85,910 long-term incentive units, respectively. During the years ended December 31, 2013, 2012 and 2011, certain employees were also granted an aggregate of 95,316,86,843 and 98,632 long-term incentive units, respectively, which, in addition to a service condition, are subject to a performance condition that impacts the number of units which ultimately vests. The performance condition is based upon our achievement of the respective fiscal years’ Core Funds From Operations, or CFFO, per share targets. Upon evaluating the results of the performance condition, the final number of units is determined and such units vest based on satisfaction of the service conditions. The service conditions of the awards provide for 20% vesting on each of the first and second anniversaries of the grant date and 30% vesting on each of the third and fourth anniversaries of the grant date, provided the grantee continues employment on each anniversary date. Based on our 2013, 2012 and 2011 CFFO per diluted share and unit, 75,105of the 2013 long-term incentive units, net of forfeitures and 78,118 of the 2012 long-term incentive units, net of forfeitures, respectively, and all of the 2011 long-term incentive units, respectively, satisfied the performance condition. The grant date fair values, which equal the market price of Digital Realty Trust, Inc. common stock, are being expensed on a straight-line basis for service awards over four years, the current vesting period of the long-term incentive units. For performance based awards, we expense the fair value using an accelerated method with each vesting tranche valued as a separate award.  

The expense recorded for the years ended December 31, 2013, 2012 and 2011 related to long-term incentive units was approximately $8.9 million, $9.0 million and $8.7 million, respectively. We capitalized amounts relating to compensation expense of employees direct and incremental to construction and successful leasing activities of approximately $1.6 million, $1.1 million and $0.8 million for the years ended December 31, 2013, 2012 and 2011, respectively. Unearned compensation representing the unvested portion of the long-term incentive units totaled $12.9 million and $13.3 million as of December 31, 2013 and 2012, respectively. We expect to recognize this unearned compensation over the next 2.5 years on a weighted average basis.

(b) Class C Profits Interest Units

On May 2, 2007, we granted awards of Class C Profits Interest Units of the Operating Partnership or similar stock-based performance awards, which we refer to collectively as the Class C Units, under the Amended and Restated 2004 Incentive Award Plan (2007 Grant) to each of our named executive officers and certain other officers and employees.

The Class C Units subject to this award were subject to vesting based on the achievement of a total stockholder return (which we refer to as the market condition) as measured on November 1, 2008 (which we refer to as the first measurement date) and May 1, 2010 (which we refer to as the second measurement date).

We previously determined that the market condition with respect to the first measurement date was not achieved. On May 1, 2010, we determined that 593,316 of the Class C Units and 20,169 shares of restricted stock subject to the 2007 Grant satisfied the market condition on the second measurement date (May 1, 2010), with the value of these units equal to the maximum amount of the award pool payable pursuant to the 2007 Grant on the second measurement date. Of the Class C Units that satisfied the market condition on May 1, 2010, 60% vested on May 1, 2010 and the remaining 40% vested ratably each month through April 30, 2012.

The fair value of the 2007 Grant was measured on the grant date using a Monte Carlo simulation to estimate the probability of the multiple market conditions being satisfied. The Monte Carlo simulation uses a statistical formula underlying the Black-Scholes and binomial formulas, and such simulation was run approximately 100,000 times. For each simulation, the value of the payoff was calculated at the settlement date and was then discounted to the grant date at a risk-free interest rate. The expected value of the Class C Units on the grant date was determined by multiplying the average of the values over all simulations by the number of outstanding shares of Digital Realty Trust, Inc. common stock and Operating Partnership units. The valuation was performed in a risk-neutral framework, so no assumption was made with respect to an equity risk premium. Other significant assumptions used in the valuation included an expected term of 36 months, expected stock price volatility of 23%, a risk-free interest rate of 4.6%, and a dividend growth rate of 5.0%. The fixed award limit under the plan was $17 million for the first market condition and $40 million for the second market condition, and there were 69.2 million shares of Digital Realty Trust, Inc. common stock and Operating Partnership units outstanding as of the 2007 Grant date. The grant date fair value of these awards of approximately $11.8 million was recognized as compensation expense on a straight-line basis over the expected service period of five years, which ended during the three months ended June 30, 2012.

We recognized compensation expense related to the Class C Units subject to the 2007 Grant of $0.5 million and $2.0 million for the years ended December 31, 2012 and 2011, respectively. We capitalized amounts relating to compensation expense of employees direct and incremental to construction and successful leasing activities of approximately $0.1 million and $0.3 million for the years ended December 31, 2012 and 2011, respectively.

(c) Stock Options

The fair value of each option granted under the Amended and Restated 2004 Incentive Award Plan is estimated on the date of the grant using the Black-Scholes option-pricing model. For the years ended December 31, 2013, 2012 and 2011, no stock options were granted. The fair values are being expensed on a straight-line basis over the vesting period of the options, which ranges from four to five years. All unearned compensation has been recognized as of December 31, 2012.  The expense recorded for the years ended December 31, 2012 and 2011 was approximately $0.2 million and  $0.8 million, respectively. We capitalized amounts relating to compensation expense of employees direct and incremental to construction and successful leasing activities of approximately $0.1 million and  $0.2 million for the years ended December 31, 2012 and 2011, respectively.

The following table summarizes the Amended and Restated 2004 Incentive Award Plan’s stock option activity for the year ended December 31, 2013:

	Year Ended December 31, 2013
	Shares	Weighted average exercise price
Options outstanding, beginning of period	129,259	$              30.61
Exercised	(5,569)	41.24
Cancelled / Forfeited	-	-
Options outstanding, end of period	123,690	$              30.13
Exercisable, end of period	123,690	$              30.13

The following table summarizes information about stock options outstanding and exercisable as of December 31, 2013:

Options outstanding and exercisable
Exercise price	Number outstanding	Weighted average remaining contractual life (years)	Weighted average exercise price	Aggregate intrinsic value
$12.00 - 13.02	34,870	0.82	$          12.00	$      1,294,374
$20.37 - 28.09	17,000	1.89	21.28	473,310
$33.18 - 41.73	71,820	3.29	41.02	581,417
	123,690	2.40	$          30.13	$      2,349,101

(d) Restricted Stock

During the years ended December 31, 2013, 2012 and 2011, certain employees were granted an aggregate of 79,114,  46,617 and 41,220 shares of restricted stock, respectively. During the years ended December 31, 2013, 2012 and 2011, certain employees were also granted an aggregate of 69,995,  52,947and 50,999 shares of restricted stock, respectively, which, in addition to a service condition, are subject to a performance condition that impacts the number of shares which ultimately vests. The performance condition is based upon our achievement of the respective year’s CFFO per share targets. Upon evaluating the results of the performance condition, the final number of shares is determined and such shares vest based on satisfaction of the service conditions. The service conditions of the awards provide for 20% vesting on each of the first and second anniversaries of the grant date and 30% vesting on each of the third and fourth anniversaries of the grant date provided the grantee continues employment on each anniversary date. Based on our 2013, 2012 and 2011 CFFO per diluted share and unit, 50,805 shares of the2013 restricted stock awards (net of forfeitures) and 49,325 shares of the 2012 restricted stock awards (net of forfeitures) and all of the 2011 restricted stock, respectively, satisfied the performance condition.

The grant date fair values, which equal the market price of Digital Realty Trust, Inc. common stock, are being expensed on a straight-line basis for service awards over the vesting period of the restricted stock, which ranges from three to four years. For performance based awards, we expense the fair value using an accelerated method with each vesting tranche valued as a separate award.

The expense recorded for the years ended December 31, 2013, 2012 and 2011 related to grants of restricted stock was approximately $2.7 million, $2.9 million and $2.0 million, respectively. We capitalized amounts relating to compensation expense of employees direct and incremental to construction and successful leasing activities of approximately $2.5 million, $2.1 million and $1.5 million for the years ended December 31, 2013, 2012 and 2011, respectively. Unearned compensation representing the unvested portion of the restricted stock totaled $8.7 million and $7.4 million as of December 31, 2013 and 2012, respectively. We expect to recognize this unearned compensation over the next 2.8 years on a weighted average basis.

(e) 401(k) Plan

We have a 401(k) plan whereby our employees may contribute a portion of their compensation to their respective retirement accounts, in an amount not to exceed the maximum allowed under the Code. The 401(k) Plan complies with Internal Revenue Service requirements as a 401(k) Safe Harbor Plan whereby discretionary contributions made by us are 100% vested. The aggregate cost of our contributions to the 401(k) Plan was approximately $2.4 million, $2.0 million, and $1.5 million for the years ended December 31, 2013, 2012 and 2011, respectively.