Big deal for Archstone.

The biggest deal of the year was so big it needed two buyers.

Arlington, Va.-based AvalonBay Communities Inc. and Chicago-based Equity Residential announced in February they had completed the acquisition of Archstone Enterprise LP for $16 billion. Archstone is an Englewood-based apartment developer and operator acquired by Lehman Brothers Holdings Inc., in .2007. The defunct investment bank, which filed for bankruptcy in 2008, sold the apartment company to pay off creditors.

Archstone-Smith was once a publicly traded real estate investment trust (REIT). It was purchased by Lehman Brothers and Tishman Speyer Properties iii 2007 for $23 billion and taken private. Since then the apartment company shortened its name to Archstone, and Lehman bought...