European banking stocks headed for their largest one-day fall in nine months on Friday, a day after a sharp sell-off in U.S. banks.

Europe's STOXX banking index fell 4.2%, set for its biggest one-day slide since early June, with declines for most major names including HSBC down 4.5% and Deutsche Bank down 7.9%.

S&P 500's bank index finished down 6.6% on Thursday after tech-industry lender SVB Financial Group launched a share sale to shore up its balance sheet due to declining deposits from startups struggling for funding. (Reporting by Alun John; Editing by Amanda Cooper)