Geico Corp. yesterday reported a 6 percent increase in profits for the first half of the year as improved underwriting results in the second quarter boosted earnings following an essentially flat first three months of the year.

The Chevy Chase-based property-casualty insurer noted that growth in premium and investment income boosted total revenue to $952.8 million for the six-month period, up 3 percent from $925.5 million in the same period the year before.

For the first half, Geico earned $94.7 million ($6.16 a share), compared with $89.2 million ($5.76) for the first six months of 1989.

Net income for the second quarter totaled $48.3 million ($3.15), up from $43.7 million ($2.82) in the same period of 1989. Revenue totaled $489.3 million in the quarter, up 3 percent from $473.3 million in the 1989 second quarter.

Geico Chairman William Snyder noted that weather-related catastrophe losses were down sharply for the second quarter and second-quarter underwriting results "were quite favorable, but because first quarter results were less favorable," the company's consolidated underwriting results for the six months deteriorated slightly to 97.5 percent from 96.7 percent.

This figure represents the percentage of each dollar in premiums that is paid out in claims and expenses.

"We are just generally satisfied with the results of the second quarter, but we caution people not to put too much emphasis on an individual quarter," said Carroll R. Franklin, Geico's director of investor relations. "We believe things are going reasonably well."

Geico reported assets of $3.47 billion as of June 30, compared with $3.43 billion the year before. Shareholders' equity was $970.7 million on June 30, up from $898.1 million in 1989.

Integral Systems Inc., a Lanham-based company that provides computer hardware and software for the federal government and commercial clients, said two federal contracts helped push its profits up 52 percent in the first nine months of its fiscal year ended June 30.

Integral reported nine-month earnings of $732,009 (80 cents), compared with $480,088 (53 cents) in the first nine months of fiscal 1989. Revenue increased 58 percent in the first nine months, to $8.97 million from $5.66 million in the same period a year earlier.

For the fiscal third quarter, Integral said it earned $245,323 (27 cents), up 43 percent from fiscal 1989 third-quarter earnings of $171,160 (19 cents). Revenue climbed 49 percent in the third quarter, to $3.04 million from $2.04 million.

The company said the two contracts that aided its earnings growth were with the National Oceanic and Atmospheric Administration and involved an unusually high level of computer hardware sales. They cover a $4 million computer system designed to collect and process weather satellite information, and an $8 million system for controlling and monitoring polar weather satellites.