After turning in its best annual performance in 144 years of writing insurance in the District, Firemen's Insurance Co. has just recorded its worst quarter on record, stockholders were told yesterday.

Chairman and President Herbert M. Pasewalk said the company has paid out $904,178 in claims through March, a "drastic increase in losses." But he also assured shareholders that the company expects to recover by the end of the year, assuming its usual rate of a 12 percent to 15 percent increase in new premiums.

Many of the losses were because of theft claims, Pasewalk said, and the company is working on programs to decrease those losses, such as incentives for policyholders who install deterrents.

During 1980, the D.C. insuror had a net profit of $537,298, which translates to $10.75 a share on 50,000 shares outstanding, the highest pershare earnings in the company's history. The company's total admitted assets of $8.71 million are a record and more than double Firemen's assets just after the 1969 riots in the District, Pasewalk said.

One of the figures by which insurance companies are judged from an investment viewpoint is the combined loss ratio (losses and expenses).At Firemen's this ratio is 93.76 percent, Pasewalk said. That's a relatively low figure in the insurance business and an indicator of Firemen's financial base. He mentioned that the combined loss ratio of another insuror, a giant of the industry, climbed to 105.9 percent during 1980.

Pasewalk and Richard H. Winkelman, executive vice president and treasurer, said they couldn't attribute 1980's profit feat to any one thing. But Pasewalk, who characterized the insurance business as often being "a crapshoot," said Firemen's didn't experience its usual heavy losses from wind damage claims last fall, thus helping the company reach its record levels. w

Firemen's operating out of its 99-year-old historic building at 303 7th St. NW, is again the target of merger talks, Pasewalk revealed. Securities and Exchange Commission rules prevented him from discussing the details; however, he did say one was a stock brokerage firm and the other was a Belgian insurance conglomerate.