LEON D. BLACK 445 Park Avenue Suite 1401 New York, New York 10022 December 2014 Martin Nowak, Director Program for Evolutionary Dynamics Harvard University One Brattle Square, Suite 6 Cambridge, Massachusetts 02138-3758 Re: $4,000,000 Irrevocable Pledge by Leon D. Black to Harvard University For Use and Benefit of Program for Evolutionary Dynamics (this "Pledge") Dear Dr. Nowak: In consideration of the excellent work now and hereafter conducted by the Program for Evolutionary Dynamics at Harvard University ("PED"), and with the understanding that PED will be relying hereon in projecting its fiscal needs, seeking other support and allocating its limited resources for continuing such work in the future, I, the undersigned donor, intending to be legally bound, hereby irrevocably pledge and promise to pay to PED the aggregate sum of Four Million Dollars ($4,000,000) as hereinafter provided. I will fulfill this Pledge with an outright gift in the amount of Two Hundred Fifty Thousand Dollars ($250,000), which I shall pay on the date hereof, and with an outright gift of the remaining balance of Three Million Seven Hundred Fifty Thousand Dollars ($3,750,000), which I shall pay by not later than September 30, 2015 (the "Final Payment Date"). I may accelerate the payment of any or all of the unpaid funds required under this Pledge at any time in my discretion so long as the cumulative total of all such payments hereunder equals Four Million Dollars ($4,000,000) and is paid in full by the Final Payment Date. All payments under this Pledge shall be made by wire transfer of immediately available funds for the sole benefit of PED to an account of Harvard University maintained at Bank of America in accordance with the following wire transfer instructions: Name of Bank: Bank Address: ABA No.: DDA Acct. No.: Wire Details: Bank of America 100 Federal Street Boston, MA 02110 President and Fellows of Harvard College RSO Acct) For Sole Use and Be