Government Employees Life Insurance Co. reported lower earnings for the second quarter and first half of 1981, despite a 17 percent increase in investment income due to high interest rates.

The Geico Corp. life insurance subsidiary reported quarterly profits of $1.99 million (45 cents) a share, down from $2.13 million (48 cents) last year. For the first half, Government Employees Life earned $3.95 million (89 cents) compared with $4.07 million (91 cents) in the first half of 1980.

The company said the lower earnings were due largely to bigger benefit payments and more policy cancellations.

Bucking the trend in the thrift industry, John Hanson Savings and Loan reported records earnings of $475,000 (40 cents a share) for the fiscal year ended June 30.

The profits contrasted with a loss of $209,000 (18 cents) during the previous year.

Chairman Charles Dukes Jr. said the turnaround was due to "agressive lending practices and tighter management controls." Luring customers with higher rates, John Hanson posted a 28 percent increase in deposits to $163 million and increased its assets 33 percent to $193.7 million.

Old Dominion Real Estate Investment Trust reported net income of $24,000 (3 cents) for the second quarter, up from $17,400 (2 cents) last year. First half profits climbed to $561,200 (78 cents) from $422,600 (60 cents); sales of real estate contributed $528,200 to this year's first half earnings and accounted for $384,500 of the profits in the same period a year ago.

The Richmond, Fredericksburg and Potomac Railroad Co. reported second quarter earnings jumped 19 percent to $4.47 million ($12.44) from $3.76 million ($10.50) last year. Operating revenues for the quarter increased 13 percent to $14.1 million.

yfor the first half of the year, pre-tax earnings increased 25 percent, but net profits declined slightly, because the company did not have the benefit of investment tax credits that aided last year's profits. First half net totaled $8.417 million ($23.43) compared with $8.422 million ($23.49) in the same period a year ago.

Commonwealth Natural Resources Inc. said second quarter earnings increased 20 percent to $1.27 million ($1.09) from $1.05 million (90 cents) and first half earnings were up slightly, to $4.24 million ($3.65) from $4.19 million ($3.58). The Richmond natural gas and propane supplier reported total sales of $133 million for the six months, up from $110.6 million and quarterly sales of $56.2 million, up from $40.5 million.

HGIC Corp., the parent of Home Guaranty Insurance Co. of Richmond, reported second quarter profits increased to $125,000 from $102,000, but earnings per share dropped to 7 cents from 11 cents because of a large stock sale.

Earnings for the six months ended June 30 totaled $270,000 (16 cents) com