Twitter cofounder Ev Williams just sold $47 million worth of stock

Twitter cofounder Evan Williams sold 1.8 million shares of Twitter stock on Monday, netting about $47 million, according to a new SEC filing.

Williams is one of the cofounders of the company, and served as its CEO from 2008 to 2010.

There's reportedly some bad blood between Williams and Jack Dorsey, the CEO and fellow cofounder. Dorsey is also the head of Square, which just filed to go public.

Williams is usually cited as the driving force who got Dorsey fired in the first place so Williams could take his place. Then, according to a profile of Dorsey in The New Yorker, some insiders believe that Dorsey used his position on the board to oust Williams in 2010 and replace him with Dick Costolo. Costolo resigned in June, paving the way for Dorsey's return this year.

Williams managed a lukewarm blog post welcoming Dorsey back as full-time CEO in October, writing, "I honestly didn't think we'd land on Jack when we started unless he could step away from Square."

He remains on the board of directors.

Williams has sold blocks of shares in the past, including almost 400,000 worth about $24 million in April. But that sale was exercised as part of a preplanned schedule, according to a note in the SEC filing accompanying it. The form for yesterday's filing had no such note and was significantly larger.

Williams and Twitter did not immediately respond to requests for comment.