Citigroup shareholders nix massive CEO bonus

Citigroup (C 0.00%) shareholders dealt a harsh blow to CEO Vikram Pandit on Tuesday, rejecting his $15 million pay package at Citi's annual meeting in Dallas.

The vote is non-binding -- meaning that Citi's board of directors could ignore it -- but it's still a rare slap in the face for the head of a major U.S. company, and the directors say they're going to take another look at pay for Pandit and four other senior executives.

What brought about this unprecedented display of investor rancor? Here, a guide.

Read the rest here.