The Association of Mortgage Investors wants trustees of residential mortgage-backed securities "to hold servicers accountable for negligence in maintaining the assets of trusts." The Washington firm, which advocates on behalf of institutional and private MBS investors, said in a press release that the recently uncovered robo-signing debacle – first reported by HousingWire two weeks ago – "undermines the integrity and the operational framework of the housing finance and mortgage system as it exists today." Most of the nation's largest mortgage lenders, including Bank of America, Ally Financial, formerly GMAC Mortgage, and JPMorgan Chase, have suspended foreclosures to amend faulty affidavits that may have been signed without looking at the documents or a notary present. The AMI wants bond trustees to investigate the process and assure investors that mortgages bundled and sold into MBS are repurchased by the loan originators, who failed in their "fiduciary responsibilities [to] protect millions of American pensioners and retirees." "The capacity constraints at our nation’s largest servicers continue to be an issue of great concern to investors," said Chris Katopis, executive director of the AMI. "We urge Ally, JPMorgan Chase, and all other servicers to invest the time and resources necessary to improve their operational infrastructure and to avoid situations where efficient mortgage servicing and collection practices are compromised." He said the may snafus may cause inaccurate legal filings for the mortgages and underlying properties in the MBS pools. "The unfortunate and little-known consequence of these operational breakdowns is the destruction of capital needed to sustain fixed-income investors reliant upon cash flow from pensions and retirement accounts," Katopis said. Write to Jason Philyaw.