U.S. lawmakers have penned a letter pressing Federal Reserve Chairman Jerome Powell for information on American banks’ ties to crypto following the collapse of FTX. 

“Banks’ relationships with crypto firms raise questions about the safety and soundness of our banking system and highlight potential loopholes that crypto firms may try to exploit to gain further access to banks,” Wednesday’s letter said. 

The senators referred to Alameda Research’s $11.5 million investment in Washington bank Moonstone in their letter—and noted other U.S. bank’s “heightened volatility” due to crypto investments.