Shares of State Street fell 4 per cent yesterday on worries about the company's more than $20 billion (€14.67 billion) in commitments to asset-backed commercial paper programmes.

State Street recently said in US regulatory filings that it administers four, third-party owned asset-backed commercial paper programmes, or conduits.

Banks rely heavily on these conduits for cheap, short-term funding, but if they cannot continue to access this debt they could face a credit squeeze.

At the end of June, State Street disclosed nearly $29 billion in off-balance-sheet conduit assets.

The Boston-based bank does not hold any equity interest in the conduits. However, State Street is exposed to the conduits because it provides back-up lines of credit to them. Its commitment under liquidity asset purchase agreements and back-up lines of credit totalled about $28 billion at the end of June, according to the company's financial statements.

State Street has said potential losses, if any, from these conduits' activities are not expected to have a material impact on its results. The company was not available for comment.

State Street, which now employs 2,000 people in Ireland following its acquisition of Investors Financial Services, is the world's largest institutional money manager. State Street shares fell $2.58 to $61.30 in early trade on the New York Stock Exchange