New York, March 21 : JPMorgan Chases investment bank has been hired to advise First Republic, as the embattled regional bank tries to ease concerns about its financial condition, a media report said. First Republic's share price has plummeted 90 per cent to record lows over the past month, as investors scrutinised lenders with a high amount of uninsured depositors ?? a response to the collapse of Silicon Valley Bank and Signature Bank earlier this month, CNN reported. First Republic's nosedive continued even after 11 of America's biggest banks, including JPMorgan, Citigroup and Wells Fargo, provided First Republic with a $30 billion rescue last week. Despite that effort, both Moody's and S&P Global Ratings downgraded First Republic's credit ratings over the weekend. Now, the San Francisco-based First Republic has hired JPMorgan's investment bank to help management explore its options, including potentially raising additional capital, CNN reported. First Republic shares rallied 22 per cent in premarket trading on Tuesday, rebounding from a 47 per cent plunge on Monday. Jim Herbert, First Republic's founder and executive chairman, and CEO Mike Roffler had last week expressed their "deep appreciation" to the big banks for their $30 billion lifeline, CNN reported. "Their collective support strengthens our liquidity position, and reflects the ongoing quality of our business, and is a vote of confidence for First Republic and the entire US banking system," the First Republic executives said in a statement issued last week. /IANS