Giant Food Inc. yesterday reported a 27 percent increase in profits from continuing operations in the year ended Feb. 25. Earning also rose at Federal National Mortgage Association but declined sharply for Smith's Transfer Corp.

Landover-based Giant, one of the Washington area's two major supermarket chains, reported fiscal year profits of $13.6 million ($4.14 a share) compared with $10.7 million ($3.25) in the previous year.

Not reflected in these earnings from continuing operations are losses associated with the closing of Giant's four major department stores and a group of carpet centers.

The closing of the nonfood stores resulted in a loss of $3.8 million for discontinued operations, which reduced final net income to $9.8 million ($2.98 a share) from $10.6 million ($3.22) the precious year, when Giant had a loss of $103,000 from discontinued operations.

Sales from continued business rose more than 11 percent to $936 million. Including sales of the closed stores, sales of the year totaled $992 million.

In the fourth quarter alone, Giant profits from continuing operations jumped 45 percent to $5.1 million ($1.57) from $3.5 million ($1.06), as sales increase 14 percent to $312 million.

After a quartely loss of $2.7 million from discontinued operations, final net income for the fourth period was $2.4 million (73 cents) vs. $4 million ($1.20) a year earlier, when the closed businesses contibuted profits of $472,000.

The final quarter include $330,000 (10 cents) of earnings due to an under-estimate of investment tax credits in prior quarters.

After closing the four department stores and carpet stores in February, Giant now operates 42 food-drug units, 73 food stores, 26 Pants Corrals that feature Levi's merchandise, 3 garden centers, 8 optical shops and a gas station.

Federal National Mortgage Association, a Washington firm that supports a secondary market in home mortgages, reported that first-quater profits rose to $52 million (87 cents a share) from $42.8 million (72 cents) in the same period last year.

In the recent quarter, Fannie Mae earned $70.1 million from yields on its mortgage portfolio compared with $59.6 million in the 1977 period.

Smith's Transfer Corp. a trucking firm in Staunton. Va. reported that first-quarter profits plummented to $166.149 (7 cents a share) from $14 million (57 cents) in the 1977 period. Revenues rose to $52 million from $40 million.

A company statement attributed the decline primarily to severe winter weather. Another factor was low revenues on some recently acquire trucking routes in the South. Smith's said it expects improved earnings as 1978 progresses.

United Virginia Bankshares Inc. of Richmond reported a sharp increase in operating profits for the first quarter. Earnings totaled $5.4 million ($1.01 a share) compared with $3.4 million (63 cents) in the same period of 1977.

Final net income for UNB, the largest banking company in the state, was the same as operating earnings with monor securities gains or losses in both periods.

National Savings & Trust Co. of Washington reported that first-quarter profits jumped 31 percent to $845-292 ($1.85 a share) from $646.159 ($1.41) in the same period last year.

Directors approved a regular quarterly dividend of 65 cents a share, payable May 1 to stockholders of record April 21.