Our long-standing practices and policies specify that all stock-based compensation awards are approved by the Compensation Committee (the Committee) of the Board of Directors. The award approval process specifies the grant date, value and terms of the award. The same terms and conditions are consistently applied to all employee grants, including Officers. The Committee approves all individual Officer grants. The number of stock-based compensation award units included in an individual’s award is determined based on the methodology approved by the Committee. The exercise price methodology approved by the Committee is the closing price of the Company stock on the date of the grant. In June of 2014, shareholders approved the Caterpillar Inc. 2014 Long-Term Incentive Plan (the Plan) under which all new stock-based compensation awards are granted. In June of 2017, the Plan was amended and restated. The Plan initially provided that up to 38,800,000 Common Shares would be reserved for future issuance under the Plan, subject to adjustment in certain events. Subsequent to the shareholder approval of the amendment and restatement of the Plan, an additional 36,000,000 Common Shares became available for all awards under the Plan. 

Common stock issued from Treasury stock under the plans totaled 5,126,379 for 2019, 5,590,641 for 2018 and 11,139,748 for 2017. The total number of shares authorized for equity awards under the amended and restated Caterpillar Inc. 2014 Long-Term Incentive Plan is 74,800,000, of which 40,754,720 shares remained available for issuance as of December 31, 2019. 

Stock option and RSU awards generally vest according to a three-year graded vesting schedule. One-third of the award will become vested on the first anniversary of the grant date, one-third of the award will become vested on the second anniversary of the grant date and one-third of the award will become vested on the third anniversary of the grant date. PRSU awards generally have a three-year performance period and cliff vest at the end of the period based upon achievement of performance targets established at the time of grant. 

Upon separation from service, if the participant is 55 years of age or older with more than five years of service, the participant meets the criteria for a “Long Service Separation.” Award terms for stock option and RSU grants allow for continued vesting as of each vesting date specified in the award document for employees who meet the criteria for a “Long Service Separation” and fulfill a requisite service period of six months. Compensation expense for eligible employees for the grants was recognized over the period from the grant date to the end date of the six-month requisite service period. For employees who become eligible for a “Long Service Separation” subsequent to the end date of the six- month requisite service period and prior to the completion of the vesting period, compensation expense is recognized over the period from the grant date to the date eligibility is achieved. 

For PRSU awards granted in 2018 and 2017, only a prorated number of shares may vest at the end of the performance period based upon achievement of the performance target, with the proration based upon the number of months of continuous employment during the three-year performance period. Employees with a “Long Service Separation” must also fulfill a six-month requisite service period in order to be eligible for the prorated vesting of outstanding PRSU awards granted in 2018 and 2017. Compensation expense for the 2018 and 2017 PRSU grants is being recognized on a straight-line basis over the three-year performance period for all participants. Award terms for the 2019 PRSU grant allowed for continued vesting upon achievement of the performance target specified in the award document for employees who meet the criteria for a “Long Service Separation” and fulfill a requisite service period of six months. Compensation expense for the 2019 PRSU grant with respect to employees who have met the criteria for a “Long Service Separation” is recognized over the period from the grant date to the end of the six-month requisite service period. For employees who become eligible for a “Long Service Separation” subsequent to the end date of the six-month requisite service period and prior to the completion of the vesting period, compensation expense is recognized over the period from the grant date to the date eligibility is achieved. 

At grant, option awards and SARs have a term life of ten years. For awards granted prior to 2016, if the “Long Service Separation” criteria are met, the vested options/SARs have a life that is the lesser of ten years from the original grant date or five years from the separation date. For awards granted beginning in 2016, the vested options have a life equal to ten years from the original grant date. 

Accounting guidance on share-based payments requires companies to estimate the fair value of options/SARs on the date of grant using an option-pricing model. The fair value of our option/SAR grants was estimated using a lattice-based option-pricing model. The lattice-based option-pricing model considers a range of assumptions related to volatility, risk-free interest rate and historical employee behavior. Expected volatility was based on historical Caterpillar stock price movement and current implied volatilities from traded options on Caterpillar stock. The risk-free interest rate was based on U.S. Treasury security yields at the time of grant. The weighted-average dividend yield was based on historical information. The expected life was determined from the lattice-based model. The lattice-based model incorporated exercise and post vesting forfeiture assumptions based on analysis of historical data. The following table provides the assumptions used in determining the fair value of the Option awards for the years ended December 31, 2019, 2018 and 2017, respectively. 

