Martin Marietta Corp. yesterday reported that third-quarter profits increased by 25 percent, largely as a result of gains from a one-time sale of Florida real estate and a favorable ruling in a legal dispute.

Profits for the quarter were $108.8 million ($2.16 per share), up from $87.3 million ($1.65) in the same quarter last year. Company sales, though, increased by just 5 percent, to $1.49 billion from $1.42 billion.

The company said that the sales and profits were higher in all operating groups save one -- electronics and missiles, which recorded a small decline blamed on finishing the Copperhead antitank projectile program and winding down production of the Hellfire anti-armor missile.

The company boasted two major contract wins during the third quarter: a $500 million deal to produce jet engine thrust reversers for General Electric Co. and Pratt & Whitney, and a $138 million U.S. Postal Service job to produce automated mail sorting machines.

Alex. Brown Inc. said a sagging stock market cut deeply into the value of securities it traded and helped take the regional brokerage firm to a $3.1 million loss in the third quarter.

The sharp market downturn that followed Iraq's invasion of Kuwait Aug. 2 hurt the firm's investment activities across the board but did the most damage to its trading activities, where revenue fell to $1.5 million from $11 million in the same quarter a year ago.

Beverly L. Wright, chief financial officer, said the sharp drop was caused by losses on stocks that the firm holds in inventory as part of its trading activities. One of the key losses came on a stock that Alex. Brown was trading after managing a public offering on that stock.

Wright said she could not identify the specific stocks on which the firm lost money.

Investment banking activities also were off from a year earlier, falling to $20.6 million from $29 million and income from real estate investment activities dropped to $6.3 million from $10.7 million.

Overall, the market slump reduced Alex. Brown's third-quarter revenue to $58 million from $79.5 million and produced a loss of $3.1 million (21 cents a share), compared with a gain of $6.3 million (38 cents) a year earlier.

Alex. Brown President Donald B. Heeb Jr. commented, "Like other firms in the securities industry, our pace of business slowed in the latter part of the quarter as the market declined due to concerns about war in the Middle East and a recession here at home."'

The company also said yesterday it expanded its common stock repurchase program to 1 million shares, from 500,000 shares. The stock will be purchased from time to time in the open market, in block purchases or as otherwise determined by the company.