SVB's difficulties are latest example of strain in rates-sensitive parts of the U.S. economy - coming just hours after crypto-lender Silvergate said it was closing.

Shares in the California-based parent of Silicon Valley Bank slid 31% after hours on Nasdaq on Wednesday.

SVB loans money to early-stage businesses and says it banks nearly half of U.S. venture-backed technology and life-sciences companies with stockmarket listings in 2022.

Its customers' "cash burn" rose in February and is driving deposits lower than forecast, CEO Greg Becker said in a letter to investors. Combined with higher costs of capital, that is pressuring margins and income, he said.

In response, SVB said it is seeking to raise more than $2 billion, made up of $500 million from private equity firm General Atlantic and $1.75 billion via a public equity offering.

General Atlantic was not immediately available for comment outside normal business hours.

The company also liquidated most of its securities portfolio, raising $21 billion, which it plans to re-invest in shorter-term debt, while doubling its term borrowing to $30 billion.

"We are taking these actions because we expect continued higher interest rates, pressured public and private markets, and elevated cash burn levels from our clients," Becker said.

"When we see a return to balance between venture investment and cash burn - we will be well positioned to accelerate growth and profitability," he added, noting SVB is "well capitalised".

SVB also published updated outlook estimates, and forecasts a "mid thirties" percentage drop in net interest income this year - larger than the "high teens" drop it forecast seven weeks earlier.

It expects net interest margins will fall to between 1.45-1.55% this year, below its January forecast for 1.75-1.85%.

(Reporting by Ananya Mariam Rajesh in Bengaluru and Tom Westbrook in Sydney; Editing by Krishna Chandra Eluri and Jane Merriman)