The lawmakers sent a letter to Geithner in October, accusing him of "complacency" in addressing the rate-rigging scandal. They called on Geithner to establish an American-based interest rate index to replace Libor, and wanted to know how much harm had been done to American investors due to the scandal.
Now, they say the Treasury has failed to provide them with answers and repeatedly canceled attempted briefings with their staff on the matter.
The controversy over the interest rate began this summer after the British bank Barclays agreed to pay nearly half a billion dollars to settle charges with U.S. and U.K. regulators that it worked to manipulate the rate for years. Libor is set based on interbank lending reports from a group of 18 banks, including three based in the United States, and it is monitored by the British Bankers Association.
Barclays went on to charge that other banks were conspiring to rig the rate, and Geithner was swept up in the controversy as well, because concerns about Libor first emerged at the New York Federal Reserve Bank when he was running it.
Geithner defended his behavior for hours before skeptical lawmakers in July, saying he took the appropriate steps by notifying regulators in the United States and United Kingdom.
He added that the government was looking into alternatives to Libor going forward but that the rate continued to be used as a benchmark after concerns emerged because it remained the best option available.