Google’s employees couldn’t have timed the stock market’s turn any better. A day before stocks bottomed in March, Google let almost 16,000 of its workers exchange their stock options. It turned out to be the deal of a lifetime.

The average exercise price for the options held by non-executives was around $521 a share at that time. But Google’s shares were trading closer to $308 each, making the options all but worthless. So, Google repriced the options to where its stock closed on March 6.

Then something surprising happened. Like the broader market, Google’s shares began to soar. Now, the stock is around $590, and each option has a profit of roughly $280. That amounts to a potential windfall for employees at the Internet search company of more than $2 billion.