Shares in East West Bancorp Inc. shot up 15 percent Thursday after the bank said it plans to offer $150 million in preferred stock to improve liquidity and strengthen its capital base.

The secondary offering of 150,000 shares of non-cumulative perpetual convertible preferred stock will be less dilutive to common shareholders, while offering investors a high fixed 8 percent dividend, said new Chief Financial Officer Tom Tolda. It’s the first time the Pasadena bank holding company has done this type of offering.

The offering comes after the bank reported an 88 percent drop in first-quarter earnings last week.

East West, which targets the Chinese-American community, has not had the same problem as other area banks with risky residential real estate loans, but has had to take charge offs on some commercial loans. First quarter results included a $55 million provision for loan losses, which lowered earnings to $5 million.

The offering should increase the bank’s capital ratio (the percentage of the bank’s capital to its risk-weighted assets) closer to 12 percent better than its peers, Tolda said compared to 10.6 percent as of mid-March.

“We wanted to take advantage of what was happening in the marketplace and not be the last bank out there trying to raise capital,” said Tolda, who took over as CFO on Monday. “We want to make sure we are very well capitalized.”

East West shares, which closed at $12.56 in regular Nasdaq trading Wednesday, fell more than 5 percent to $11.90 in after-hours trading but quickly shot up 15 percent to $14.42 in early trading Thursday. The stock is down about 46 percent from the first of the year.