So I just got off the phone with a Treasury official who answered my lingering questions about the new executive pay regime for the TARP companies (i.e., the objects of the pay czar's recent efforts). The thing you have to keep in mind here is that there are two types of stock compensation: 1.) "stock salary" (i.e., guaranteed, base salary you just happen to receive in the form of stock rather than cash) and 2.) a bonus in the form of stock. The stock salary vests as soon as its granted but pays out over four years. So, for example, if your contract says you get $500,000 worth of stock salary for 2009, then that $500,000 worth of salary belongs to you even if you leave on January 1, 2010. (That's the vesting-upon-grant feature.) But you don't actually start receiving it for two years, by which point it may have increased or decreased in value. (You get one-third after two years, then another third after three years, and another third after four.) The theory is that this makes you more likely to stick around because you can have some effect on the stock price from inside the firm but none from the outside. But, as I say, you don't forfeit this money if you leave before its paid out.
As for the bonuses paid in stock: That stock doesn't actually vest for three years, meaning you forfeit it if you leave after, say, two years and eleven months. If you stay for three years, then it all belongs to you, but it's not actually paid out until the company pays back its bailout money.
Hope that helps...