Billionaire investor Ken Griffin’s hedge fund Citadel has taken a 5.3% stake in Western Alliance Bancorp amid turmoil in the banking sector following the collapse of Silicon Valley Bank, according to a regulatory filing released Monday. Citadel bought 5,781,968 shares of Western Alliance, according to the filing. Hedge funds own thousands of individual stocks and often trade in and out of positions quickly. However, it is rare enough for Citadel to take such large shares that it requires separate filings. A spokesman at Citadel declined to comment. WAL 5D mountain Western Alliance Bancorp Shares of the bank rallied more than 40% Tuesday after selling off 47% on Friday. The big response followed regulators’ extraordinary actions to bail out all depositors at failed Silicon Valley Bank and Signature Bank and offer additional funding to other troubled institutions. On Monday, Western Alliance said it was seeing only “moderate” outflows, and cash reserves exceeded $25 billion. The bank has total assets of $67 billion by the end of 2022. “Western Alliance has taken additional steps to strengthen its liquidity position to ensure that we are in a position to meet all of our clients’ funding needs, including increasing our lending capacity,” the bank said in a statement. Citadel outperformed the S&P 500 last month, continuing its strong performance. The flagship multi-strategy Wellington fund is up 2.8% this year through February, CNBC previously reported. The hedge fund rose 38% in 2022, marking the company’s best year yet.