Regulatory sanctions and lawsuits related to Libor manipulation represent major operational risks facing large international banks. We find a significant relation between a bank’s measure of Libor exposure and its average monthly submission, from which Libor is subsequently computed, during 1999 to 2012. The relation is stronger during the January 2005 to May 2009 manipulation period (as per Barclays settlement), for currencies and maturities with substantial notional amounts of interest rate derivatives outstanding, and for banks that have settled Libor related lawsuits. We estimate that such manipulation could have increased the market value of the panel banks by $22.76 billion.