By Medha Singh and Chuck Mikolajczak

(Reuters) -Shares of U.S. regional banks rose on Tuesday after tumbling by double-digit percentages over the past several days in the wake of the biggest bank collapse since the 2008 global financial crisis.

The collapse of Silicon Valley Bank and Signature Bank sent shockwaves through global markets, despite assurances from U.S. President Joe Biden and other policymakers that banks and deposits were safe.

First Republic Bank was up 29.17% a day after hitting an intraday record low of $17.53.

Western Alliance Bancorp’s shares jumped 9.98% as Kenneth Griffin’s Citadel Advisors LLC disclosed a 5.3% stake in the lender.

Among other regional banks, Citizens Financial Group gained 2.74%, PacWest Bancorp surged 38.26% and KeyCorp advanced 7.25%.

Charles Schwab shares were up 12.68% after CNBC reported that Chief Executive Officer Walt Bettinger said he bought 50,000 shares of the company while billionaire investor Ron Baron said he “modestly increased” his position in the stock.

The S&P 1500 regional banks sub-industry index gained 2.15% after plunging 21.6% over the past three sessions, its biggest three-day percentage drop since March 2020 and fourth-largest since 2005, prompting investors to look for bargains in the space.

“There is a lot more upside to come to get back to where they were, which is really where they belong,” said Tim Ghriskey, senior portfolio strategist at Ingalls & Snyder in New York, New York.

Rating’s agency Moody’s said it was reviewing six lenders for a downgrade.

“The contagion risk is still present if everyone simultaneously loses confidence in the banking system,” said Jack Ablin, chief investment officer at Cresset Capital.

Some industry executives and advisers believe small lenders could be forced to seek saviors if a rout in their stocks does not let up.

Banks “with higher capital ratios, smaller pools of securities relative to total assets, strong brands, and diversified funding sources should be better able to weather the current market dynamics,” said UBS Global Wealth Management Chief Investment Officer Mark Haefele in a note.

Meanwhile, a media report said a wave of customers have applied to shift their accounts to large U.S. banks such as JPMorgan Chase & Co and Citigroup Inc from smaller lenders after the collapse of Silicon Valley Bank.

Big banks rose, with JPMorgan up 1.81%, Wells Fargo gaining 4.15% and Bank of America 0.86% higher.

(Reporting by Medha Singh in Bengaluru, additional reporting by Shristi Achar; Editing by Shinjini Ganguli and David Gregorio)

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