Judge Christopher A. Boyko of Federal District Court in Cleveland dismissed 14 foreclosure cases brought on behalf of mortgage investors, ruling that they had failed to prove that they owned the properties they were trying to seize.

The pooling of home loans into securities has been practiced for decades and helped propel real estate prices in recent years as investors sought the higher yields that such mortgage trusts could provide. ... But as foreclosures have surged, the complex structure and disparate ownership of mortgage securities have made it harder for borrowers to work out troubled loans, in part because they cannot identify who holds the mortgage notes, consumer advocates say.

Now, the Ohio ruling indicates that the intricacies of the mortgage pools are starting to create problems for lenders as well.