The investment strategy is to maximize return while maintaining an appropriate level of risk to provide sufficient liquidity for benefit obligations and plan expenses. Individual plan investment allocations are determined by local fiduciary committees and the composition of total assets for all pension plans at December 31, 2020 was broadly characterized as an allocation between equity securities (28%), debt securities (60%) and other investments (12%). Contributions to pension plans were $96 million in 2020, $63 million in 2019, and $71 million in 2018, and are not expected to be material in 2021. Estimated annual future benefit payments for non-terminating plans (including lump sum payments) will be approximately $140 million in 2021 and approximately $125 million in each of the next four years and in the subsequent five year period. The principal defined contribution plan is the Bristol-Myers Squibb Savings and Investment Program. The contributions are based on employee contributions and the level of Company match. The expense attributed to defined contribution plans in the U.S. was approximately $290 million in 2020 and $200 million in 2019 and 2018, respectively. On May 1, 2012, the shareholders approved the 2012 Plan, which replaced the 2007 Stock Incentive Plan. The 2012 Plan provides for 109 million shares to be authorized for grants, plus any shares from outstanding awards under the 2007 Plan as of February 29, 2012 that expire, are forfeited, canceled, or withheld to satisfy tax withholding obligations. As of December 31, 2020, 95 million shares were available for award. Shares are issued from treasury stock to satisfy BMS’s obligations under this Plan. As part of the Celgene acquisition, BMS assumed the 2017 Stock Incentive Plan and the 2014 Equity Incentive Plan (referred together with the BMS plans as the “Plans”). These plans provided for the granting of Options, Restricted Stock Units (“RSUs”), Performance Share Units (“PSUs”) and other share-based and performance-based awards to former Celgene employees, officers and non-employee directors. Additionally, the terms of these plans provided for accelerated vesting of awards upon a change in control followed by an involuntary termination without cause. As of December 31, 2020, 23 million shares were available for award under the Celgene Plans. Outstanding Celgene equity awards were assumed by BMS and converted into BMS equity awards at acquisition. The replacement BMS awards generally have the same terms and conditions (including vesting) as the former Celgene awards for which they were exchanged. Shares are issued from treasury stock to satisfy BMS’s obligations under the Plans. CVRs were also issued to the holders of vested and unexercised “in the money” Options that were outstanding at the acquisition date. Celgene RSU holders and unvested “in the money” Options that were outstanding at the acquisition date, with awards vesting prior to March 31, 2021 are also eligible to receive CVRs. Celgene RSU holders and unvested “in the money” Options that were outstanding at the acquisition date with awards vesting after March 31, 2021 are eligible to receive a cash value of $9.00 per pre-converted Celgene RSU and “in the money” Options if all CVR milestones are achieved. The contractual obligation to pay the contingent value rights terminated in January 2021 because the FDA did not approve liso-cel (JCAR017) by December 31, 2020. Executive officers and key employees may be granted options to purchase common stock at no less than the market price on the date the option is granted. Options generally become exercisable ratably over four years and have a maximum term of 10 years. The Plans provide for the granting of stock appreciation rights whereby the grantee may surrender exercisable rights and receive common stock and/or cash measured by the excess of the market price of the common stock over the option exercise price. We primarily utilize treasury shares to satisfy the exercise of stock options. RSUs may be granted to key employees, subject to restrictions as to continuous employment. Generally, vesting occurs ratably over a three to four year period from grant date. A stock unit is a right to receive stock at the end of the specified vesting period but has no voting rights. Market share units (“MSUs”) are granted to executives. Vesting is conditioned upon continuous employment until the vesting date and a payout factor of at least 60% of the share price on the award date. The payout factor is the share price on vesting date divided by share price on award date, with a maximum of 200%. The share price used in the payout factor is calculated using an average of the closing prices on the grant or vest date, and the nine trading days immediately preceding the grant or vest date. Vesting occurs ratably over four years. 110 Contributions and Estimated Future Benefit Payments Savings Plans Note 18. EMPLOYEE STOCK BENEFIT PLANS