Warren Buffett earned $357 million in paper profits on Thursday simply on warrants related to his $5 billion equity infusion into Bank of America. Not bad for a day’s work.

In exchange for the Buffett brand name and $5 billion, the Charlotte, N.C. financial institution granted Warren Buffett the option to buy up to 700 million of its shares any time in the next 10 years for $7.14. Yesterday those warrants would’ve reaped the Omaha investor a nine-figure profit.

“The question is whether Bank of America gave too many of those warrants away to get Warren Buffett to put the $5 billion preferred investment in the company. In the end that will be the question,” says Marty Mosby, a managing director at Guggenheim Securities. The warrants give Buffett the right to purchase up to 6.5% of the company’s equity.

As part of the Buffett investment, Bank of America will also pay the famed investor $300 million — a 6% annual dividend or $821,000 a day — for a decade, on his $5 billion in preferred shares.

(Source: CNN Money)