Expected ruling may complicate transactions

A court decision expected as soon as today could negate the validity of sales of thousands of foreclosed homes in Massachusetts, causing havoc for buyers and sellers and further stalling the housing market’s recovery in hard-hit areas.

At issue is proof of ownership at the time of a foreclosure sale. During the housing boom, millions of mortgages were bundled into bonds and sold to investors, a process that resulted in lengthy and twisted paper trails that can obscure ownership. Many lenders believed they could complete foreclosure transactions and later produce formal proof they held the mortgage.