US regulators have seized Republic First Bancorp and agreed to sell it to Fulton Bank, the Federal Deposit Insurance Corp. said Friday, underscoring the challenges facing regional banks a year after the collapse of three peers. The Philadelphia-based bank, which had abandoned funding talks with a group of investors, was seized by the Pennsylvania Department of Banking and Securities. The FDIC, appointed as a receiver, said Fulton Bank, a unit of Fulton Financial, will assume substantially all deposits and purchase all the assets of Republic Bank to “protect depositors.” Republic Bank had about $6 billion in total assets and $4...