Stocks closed narrowly mixed in very dull trading Friday as many investors abandoned the market in favor of an early start to the New Year holiday weekend.

The Dow Jones industrial average, which lost 11.63 Thursday, gained 3.71 to close at 2629.21.Among broader market gauges, the New York Stock Exchange composite index added 0.17 to 179.65 and Standard & Poor's 500-stock index rose 0.43 to 328.72. The price of an average share gained 3 cents.

Declines just barely led advances 789-707 among the 2,018 issues crossing the NYSE tape. Big Board volume totaled 111,040,000 shares, up from the 102,900,000 traded Thursday when trading was delayed until 11 a.m. by a transformer fire outside a building that houses one of the exchange's key computer systems.

Stocks opened lower and drifted aimlessly in very slow trading, taking their cue from weakness in overseas markets. A snowstorm in New York kept many players away from Wall Street in favor of an early start to the holiday weekend.

Slight losses in Treasury bonds also pressured the market. Bonds were down almost 1/8 point at midday after the government reported that its index of leading economic indicators fell 1.2 percent in November and economists said the report was another reflection of an economy in recession.

Hugh Johnson, chief economist at First Albany Corp. in Albany, N.Y., said the slight strength in the Dow may have been due to traders covering some short positions, that is, acting to offset bets they had made that certain stocks would fall.

Johnson said these moves may have been made in anticipation of a year-end rally Monday.

"Some traders positioned themselves (by buying) because they believe Monday will kick off a last gasp attempt at a year-end rally," he said. "There may have been some buying in anticipation of a good move. The last day of the year is traditionally a good day."

He added, though, that most of the players active in the market Friday were day traders rather than serious investors.

"They (serious investors) are either sitting on their hands, comfortable with their performance for the year, or on vacation. My suspicion is that most are on vacation, and if they're not they should be," Johnson said. "It was very uneventful today, like watching grass grow."

On the trading floor, American Express was the most active issue, unchanged at 20 3/8.

MCA followed, up 5/8 to 69 1/8. AT&T was third, off 1/8 to 30.

Among the other blue chips, IBM lost 1/4 to 113 3/8, General Motors rose 1/8 to 34 1/2, Philip Morris fell 1/4 to 50 7/8 and Navistar gained 1/8 to 2 1/8.

Volume of NYSE-listed issues, including trades in stocks on regional exchanges and in the over-the-counter market, totaled 146,019,390 shares, compared with 128,877,690 shares traded in the previous session.

Prices closed mixed in moderate trading on the American Stock Exchange.

The Amex Market Value index rose 0.98 to 304.65. Declines led advances 293-242 among the 888 issues traded. The price of an average share rose 4 cents. Composite volume totaled 15,275,285 shares vs. 11,541,525 traded Thursday.

Energy Service led the Amex issues, up 1/8 to 2 5/8.

The National Association of Securities Dealers composite index rose 0.15 to 371.20.