Credit Suisse said it had looked into the issue as part of a probe by the Swiss competition commission that was launched in February.
Chief executive officer Brady Dougan told Le Temps newspaper on Saturday that "although the issue is complex and investigations are going on in the bank, we do not think at present that Credit Suisse faces a significant problem in this matter."
Credit Suisse told AFP: "The Swiss competition commission had launched an investigation in February against 12 banks. We are cooperating with the authorities."
British bank Barclays was fined £290 million ($452 million) after it acknowledged attempting to manipulate the Libor and Euribor rates between 2005 and 2009.
Libor (London Interbank Offered Rate) is a flagship London instrument used as an interest benchmark throughout the world, while Euribor is the eurozone equivalent.
The rates play a key role in global markets, affecting what banks, businesses and individuals pay to borrow money.