He sure doesn't need the money with probably near $50 million in options on the table!
It reminds me of Bob Knight, who gave back his entire year's salary to Texas Tech when he failed to make the NCAA tournament, or Sidney Taurel, the CEO of Lilly who took a $1 salary for 2 (or 3) years so that the rest of his compensation could be reinvested in the company to help bring it back to prominence.
And Bill Gates still doesn't get enough credit for donating something like $17 BILLION dollars to charity.