The Federal Reserve is intensifying its scrutiny of banks' efforts to shed their reliance on the London interbank offered rate (LIBOR), and has begun compiling more detailed evidence on their progress, according to multiple people with knowledge of the matter.

Banks are being asked for specifics on their LIBOR exposure, their plans for amending contracts tied to the benchmark, and the fallback provisions being utilized to facilitate the shift to alternative rates, said the people, who requested not to be named given the sensitivity of the inquiries. The move is viewed partly as way for the Fed to telegraph the urgency of the transition, but also as a prelude to concrete supervisory action in the months ahead.

Banks have less than a year before the Fed has indicated it will stop allowing them to enter into new contracts pegged to LIBOR, a bedrock of the financial system being phased out by global policymakers due to a lack of underlying trading and following a high-profile rigging scandal. Still, the rate—which underpins trillions of dollar of assets—has proven difficult to dislodge. Officials last year indicated they would delay the end of certain tenors by 18 months amid concerns over financial stability stemming in part from the industry's lack of preparation.