The portfolio consists of 12 funds that own 382 properties with a total of 31,050 units. Additional details of the sale were not disclosed, expect that neither the properties nor the tenants will be affected by the sale.

Ed Neill, senior vice president of Tax Advantaged Equity for Fannie Mae, tells GlobeSt.com that the agency is talking to a number of other investors about additional transactions. Whether or not a deal the size of the Citibank transaction will come to market is impossible to say at this stage, he says. "That depends on a number of factors."

According to Citibank officials, the company has significantly stepped up its use of low-income housing tax credits over the past several years. "Citibank values the opportunity to invest in low-income rental housing and is committed to keeping much-needed capital flowing to these properties," says Andy Ditton, managing director of Citibank Community Development, in a statement.

Nationally, in recent years, demand for low-income housing tax credits has grown, both by institutional and private equity investors. The reasons include low default rates and higher than expected returns--by some 2% according to some studies. Also, much of the housing on the Gulf Coast has been rebuilt using these credits, thus familiarizing the program to a greater audience of investors.