Mr. Allen. (Ted Thai / Getty Images)

Facebook's S-1 filing is out, and almost all the early reports were true. The company has reserved the ticker symbol FB, although it has not announced on which exchange it will debut; the working number is $5 billion and the lead underwriter is Morgan Stanley.

Reporters were also able to sniff out four other banks working on the IPO: J.P. Morgan, Goldman Sachs, Bank of America and Barclay's Capital. But one underwriter slipped through: the boutique New York-based investment bank Allen & Company, which puts on the annual Sun Valley conference that regularly attracts billionaires and media moguls. 

Allen & Co., headed by the press-shy Herb Allen Jr., also boasts former CIA director George Tenet and Bill Bradley, the former U.S. Senator and NBA hall of famer. It has a strong presence in Hollywood and also helped on Google's IPO.

The preliminary filing doesn't say what percentage each bank will get.