Archstone was one of the high-profile real estate busts that helped topple Lehman.

WSJ: Equity Residential Cuts Deal to Buy 26.5% Archstone Stake

Lehman couldn't sell the shares for 150 days after the Archstone deal, but that lockup period ended in late April.

WSJ: Lehman Selling Pieces of Stakes Acquired in Archstone Deal

Equity Residential faces several hurdles in its effort to take over Archstone.

WSJ: Equity Residential Cuts Deal to Buy 26.5% Archstone Stake

Since the Archstone transaction closed on Feb. 27, shares of Equity Residential have risen 5.8%, while AvalonBay is up 8.5%, according to FactSet.

WSJ: Lehman Keeps Apartment Sector Guessing

Archstone, which owned about 50, 000 rental units, was one of Lehman's largest investments, and the apartment owner's high leverage contributed to the demise of the investment bank in September 2008.

WSJ: Lehman Selling Pieces of Stakes Acquired in Archstone Deal

Archstone, which owned about 50, 000 rental units, was one of Lehman's largest investments, and the apartment owner's high leverage contributed to the demise of the storied investment bank in September 2008.

WSJ: Lehman Keeps Apartment Sector Guessing

The move marks the opening salvo in an attempt by Equity Residential to take control of all of Archstone, which owns stakes in about 77, 000 apartments, many concentrated in major cities.

WSJ: Equity Residential Cuts Deal to Buy 26.5% Archstone Stake

Lehman already has had discussions with investors Brookfield Asset Management Inc. and Blackstone Group LP about joining in an effort to acquire the banks' Archstone stake, according to people familiar with the matter.

WSJ: Equity Residential Cuts Deal to Buy 26.5% Archstone Stake

Equity Residential, an apartment company controlled by property tycoon Sam Zell, has reached an agreement to buy a 26.5% stake in one of its largest competitors, Archstone, in a move to ultimately control the whole company.

WSJ: Equity Residential Cuts Deal to Buy 26.5% Archstone Stake