Questions about the legality of foreclosure proceedings have prompted Minneapolis-based Old Republic National Title Insurance to decide it will no longer insure titles to homes foreclosed by JPMorgan Chase and GMAC Mortgage.

Chase and GMAC both halted foreclosure sales in 23 states and are reviewing legal filings that they say may have been signed without a notary’s presence or without verifying the supporting documents.

Most lenders will not issue a mortgage for a home without title insurance, which means even more homes will be sitting on banks’ books, empty but unable to be sold.

In addition to Chase and GMAC, Bank of America announced last week it will also stop foreclosures and examine documents in the 23 states that require court approval.

If it is shown that the servicers did not follow the law in preparing foreclosure documents, problems could arise from evicted homeowners claiming they still own their home even after someone else has bought the home.