BEVERLY HILLS, Calif. (AP) _ Columbia Savings and Loan announced Sunday that losses of $591 million in 1989 and $200 million in the first two months of 1990 have rendered the once- high flying thrift insolvent.

Columbia, which reported 1989 fourth-quarter losses of $379 million, blamed its financial problems largely on the collapse of the junk bond market. The firm had heavily invested in the high-risk securities.

The bleak announcement raised doubts over whether Columbia can remain an independently operated thrift or whether it will be taken over by the government and run by regulators.

Regardless of the outcome, deposits of up to $100,000 are safe because they are insured by the federal government.

The newly appointed head of the troubled thrift, which has 950 employees in 29 Southern California offices, said he hoped the liquidation of high-risk securities and other business practices would turn Columbia around.

Columbia also is working to comply with capital standards imposed by Congress before the Dec. 31, 1994, deadline, said Edward G. Harshfield, president and chief executive.

''We have initiated programs to reduce overhead significantly and to improve our traditional thrift operations,'' Harshfield said in a statement.

The fourth-quarter loss amounted to $19.17 per share and the yearly loss was $30.11 per share. This compares to earnings of $16 million, or 37 cents per share, in the fourth quarter of 1988 and profits of $65 million, or $1.49 per share, for all of 1988.

The company said that its shareholder's equity, or the firm's value to its stockholders, fell to minus $121 million at Feb. 28, 1990, ''rendering (Columbia) insolvent under generally accepted accounting principles.''

''Columbia anticipates that significant additional loss reserves and other asset writedowns will occur in March 1990,'' the company said.

Columbia became the latest company to suffer from the problems in the junk bond market and the latest local thrift to buckle under a slowing Southern California real estate market.

Credit loss reserves of $465.6 million and a $61.6 million net loss on real estate investments contributed to the losses.

But it was the junk bond market that has most hurt Columbia. The firm's years of success were built on investments in junk bonds, the securities that paid high interest because they funded risky ventures, mostly takeovers.

Under the leadership of former chairman Thomas Speigel, a close friend of junk bond wizard Michael Milken, Columbia had angered federal thrift regulators by amassing a huge portfolio of the high-yield, high-risk securities.

Since November, the Office of Thrift Supervision has restricted Columbia's growth, dividend payment, loan funding and other activities. Lending is now limited to residential loans not exceeding $500,000.

The federal regulators imposed the restrictions because problems with Columbia's $3.8 billion junk-bond holding caused the thrift's capital to be ''substantially inadequate.''

Currently, Columbia is not in compliance with the tangible, core and risked-based requirements set by federal regulators.

The company said it will try to achieve this compliance by ''a phased divestiture of its high-yield securities through open market sales and scheduled redemptions.''

Columbia said between August and February, it had sold about $575 million of junk bonds and other securities.

The loss in 1989 was offset partly by a gain of sales of assets which totaled $219.8 million.

Net interest income of $181 million for 1989 decreased from $218 million in 1988. For the 1989 fourth quarter, net interest income was $30 million, compared to $60 million for the same period in 1988.

Columbia's assets for 1989 totaled 9.3 billion, down from 12.7 billion in 1988.

The gain on sale of loans in 1989 increased to $99 million from $6.5 million in 1988. In the 1989 fourth quarter, the sale of loans totaled $93 million, compared to a loss of $66 million in the fourth quarter of 1988.