The deal that helped sink Lehman Brothers is now playing an important role in paying off the failed investment bank's creditors.

The Lehman estate agreed Monday to sell Archstone, the sprawling apartment complex company, to Equity Residential and AvalonBay Communities for about $6.5 billion in cash and stock.

Under the terms of the deal, the Lehman estate will receive $2.685 billion in cash, as well as shares in Equity Residential and AvalonBay worth about $3.8 billion. The two apartment companies will also assume Archstone's roughly $9.5 billion in debt.

By selling Archstone, the Lehman estate will dispose of its biggest asset, as it continues its efforts to wind itself down and pay off the firm's legions of creditors. "The sale of Archstone to Equity Residential and AvalonBay is a very positive outcome for our creditors," Owen Thomas, the chairman of Lehman's board of directors, said in a statement.