U.S. regulator Gary Gensler told CNBC that U.S. and U.K. regulators needed to implement an alternative to the scandal-plagued London Interbank Offered Rate (Libor) soon.

"[These rates] are incredibly important. Over $300 trillion of derivatives and $10 trillion in loans are based on these rates and we need to ensure they have market integrity and that they're based on fact, not fiction," Gensler told CNBC on Monday.