The €13bn Irish banks have loaned into the United States is under greater stress than expected despite the tentative economic recovery there, a major Sunday Tribune survey of all US bankruptcy and civil courts has revealed.

The survey showed a surprisingly large number of cases in recent weeks involving US property companies and other stressed consumer companies that have successfully petitioned courts for bankruptcy protection against hundreds of million of dollars in debt they owe Anglo Irish, AIB and Bank of Ireland.

The findings have implications for the value of Irish property assets going into the National Asset Management Agency and the cost to taxpayers because it had been widely believed that the American loans of the Irish banks were in better shape than those in Ireland.

US court documents show that Anglo Irish, which at €10bn, accounts for by far the largest loan book of the three Irish lenders in North America, is owed large sums by property companies who were clients of its now closed Chicago office.

Berkley Manor Apartments, owner of 470 apartments, which has filed for Chapter 11 protection, owes Anglo $31.5m, excluding mounting interest.

Ventana Hills, another property company, is seeking protection against Anglo and owes the bank €55m, according to court documents.

Anglo has also got entangled with the Chapter 11 bankruptcy petition of Capmark, one of America's largest commercial property lenders, through Anglo's Colligo Funding, a pool of commercial mortgages in the US.

In the last two weeks, Bank of Ireland has officially joined the creditor list of Extended Stay Corporation, a large hotel group which owns 680 hotels across the US, the Sunday Tribune has learned.

The Manhattan bankruptcy court documents show that Extended Stay owes Bank of Ireland International Finance as a holder of its Class C certificates $30m, and owes the bank $15m more on Class D certificates.

The court documents also show that the hotels group owes M&T, AIB's 23%-owned US bank, an unsecured $8.5m.

The largest secured creditors include Wachovia Bank and Bank of America with claims of about $1.4bn each.

In San Antonio in Texas, Txco Resources, an oil company, filed in May last year for bankruptcy protection against its suppliers and seven bank creditors, including AIB. The lenders had together loaned the company $50m in April 2007.

AIB through its Capital Markets Division and its New York branch had loaned €2.95bn into North America by last summer. At least €2.3bn of the Irish banks' €13bn in American loans could end up in the Nama.