Luxembourg financial clearing house Clearstream Banking will pay the United States $152 million to settle accusations it illegally helped Iran's central bank access the US financial system, the Treasury announced Thursday. The Treasury said that in 2007 and 2008, Clearstream held an account in a bank in New York on behalf of the Central Bank of Iran that contained $2.8 billion worth of securities, violating US controls on financial dealings with Tehran. Clearstream further transferred the CBI's interests, an act of custody and related banking services under US jurisdiction which the Treasury said constituted an "apparent violation" of the US Iranian Transactions and Sanctions Regulations. "Clearstream provided the Government of Iran with substantial and unauthorized access to the US financial system," said Adam Szubin, director of the Treasury's Office of Foreign Assets Control (OFAC). "Today's action should serve as a clear alert to firms operating in the securities industry that they need to be vigilant with respect to dealings with sanctioned parties," he said in a statement. The Treasury said Clearstream told OFAC officials in 2008 it would terminate its business with Iranian clients. But it transferred the CBI's assets to another European bank's newly opened custody account at Clearstream. "This new custody account allowed the CBI to continue holding its interests in the securities through Clearstream's omnibus account in the United States," the Treasury said. Clearstream "had reason to know" that the CBI still retained beneficial ownership of the securities, it said. The Treasury, however, added that the settlement announced Thursday was lower than it could have been due to Clearstream's strong response of strengthening its compliance with US sanction rules.