Late Friday, the Lehman Brothers estate submitted an updated accounting of the fees it has paid to bankruptcy advisers through the end of January, and that tab now stands at $641.9 million and could well reach the $1 billion mark, according to Bloomberg and the estate’s SEC filing.

According to our math, a smidgen less than half of that amount has gone to the various law firms working for Lehman and its creditors. A total of 15 law firms (not including the estate’s fee examiner) have billed Lehman $310,791,000 since Lehman filed for bankruptcy on Sept. 15, 2008. Not surprisingly, Weil, Gotshal & Manges, Lehman’s lead debtor counsel, leads the way among the law firms, racking up total fees and costs of about $149.5 million over that 16-month period. That’s hardly surprising given that the Lehman case is widely considered the most complex bankruptcy in, well, the history of bankruptcy, and, according to various court filings, Weil has had some 500 total lawyers work on the case at some point during the proceedings.