Zynga, the fast-growing social gaming site, said it had hired Allen & Coinvestment banker David Wehner as its new CFO He replaces Mark Vranesh, who becomes Chief Accounting Officer, reporting to Wehner.

The move is yet another indication that the San Francisco-based start-up is prepping for an initial public offering, rounding out its executive team, which is headed by Founder and CEO Mark Pincus.