USF&G Corp., the Baltimore-based multiline insurer, posted second-quarter profits sharply off last year's figures, but Computer Data Systems, which split its stock two-for-one this summer, reported higher profits.

USF&G reported its earnings for the quarter fell to $17.9 million (62 cents a share) from $41.3 million ($1.47) in the 1981 period, while revenues declined to $573.6 million from $580.8 million.

For the six months just ended, net income from operations fell to $52.98 million ($1.85) from $87.3 million ($3.11) for the first half of last year. Revenue for the period increased to $1.15 billion from $1.14 billion a year ago.

Computer Data Systems of Bethesda said its earnings for the year ended June 30 rose to $1.2 million (83 cents) from $1 million (69 cents) in the previous 12 months. Its revenues jumped 56 percent to $25.7 million from $16.5 million.

Start-up costs for a large contract and lower profit margins in the processing divisions cut into profits, however, according to Chairman Clifford M. Kendall.

Second-quarter profits at Washington Corp. of Chevy Chase rose to $1.5 million (61 cents) from $901,170 (38 cents) in the same period last year, while revenues grew to $2.2 million from $456,000.

For the half, Washington Corp. posted earnings of $1.3 million (54 cents) compared with $1.1 million (45 cents) last year. Six-month revenues climbed to $2.5 million from $916,000. The company said its profits for the half primarily resulted from the sale of two tracts of land.

Springfield-based Isomet Corp. posted earnings of $84,000 (5 cents a share) on revenues of $889,000 during the second quarter, compared with $198,000 (13 cents) on revenues of $949,000 during the year-earlier period.

For the half, revenues grew to $2 million from $1.9 million. Profits were $247,000 (16 cents) compared with $532,000 (35 cents) last year.

Pulaski Furniture of Pulaski, Va., reported third-quarter earnings of $211,000 (30 cents) compared with last year's $429,000 (60 cents). Third-quarter sales increased to $11 million from $10.3 million.

For the latest nine months, profits climbed to $921,000 ($1.31) from $544,000 (76 cents), while sales increased to $31.2 million from $30.5 million.

Pulaski's reduced profits in the latest quarter reflect higher production costs and lower production, while sales figures reflect higher prices to consumers.

Buoyed by strong sales of its universal life policy, The Life Insurance Company of Virginia reported a 43.4 percent increase in individual-life sales volume in the second quarter, to $454.1 million compared with $316.7 million last year. Individual life insurance in force grew by $185.4 million in the second quarter, compared with growth of $92.7 million during the same period of 1981. The average face amount of a life policy sold during the period increased 45.7 percent to $45,768 from $31,410 in the comparable period last year.

The Richmond-based company, part of The Continental Group Inc., was the first major life insurance company to introduce a universal life policy.

MIW Investors of Washington said the trust had net income of $422,551 (11 cents) for the fiscal year ended March 31, an improvement over last year when the company reported a loss of $241,385.

This is the first time since 1974 that MIW has posted positive net operating income, and it is the first time since the recession of the mid-1970s that its annual average rate of return from its investment portfolio exceeded its cost of capital, MIW said.

As part of a continuing drive that reduced non-earning assets of the trust from 55 percent of the portfolio to 22 percent last year, MIW reported that Hospital Corp. of America will buy its 23-acre commercial site in Margate, Fla., for $2 million, a move that will further reduce non-earning assets to 16 percent of the portfolio.

First American Bank of Maryland reported that its second-quarter earnings increased 53 percent to $671,000 (69 cents) from $439,000 (44 cents) for the same period last year. After securities transactions, profits were $646,000 (66 cents) this year. There were no securities gains or losses during the second quarter of 1981.

In the first six months, the Silver Spring-based bank had net income of $1.2 million ($1.26) versus $855,000 (86 cents) for the first half of 1981. First American President Paul G. Adams attributed the improved operating results to an increase in net interest income resulting from restructured asset-liabilty mix, an increase in fee income and a reduced rate of growth in operating expenses.