Dow Climbs Another 18.98 to Record High : GM Plans, Reagan Talk Spur Investor Confidence

The stock market rolled up another gain to record highs Thursday, following through on its sharp rise in Wednesday’s session.

The Dow Jones average of 30 industrials climbed 18.98 to 2,276.43, bringing its gain during the past three sessions to 55.96 points.

Volume on the New York Stock Exchange reached 205.43 million shares, up from 198.41 million Wednesday. It was the heaviest total in more than two weeks.

Analysts said that the market was benefiting from a new mood of confidence inspired earlier in the week by General Motors Corp.’s announced plan to buy back as much as 20% of its stock during the next four years. The move carried the suggestion that prices of important stocks such as GM’s remain at levels where major investors find them attractive to buy.

GM Stock Falls

GM shares dropped 1 3/8 to 78 1/8 in active trading, however, after jumping 3 7/8 Wednesday.

Point-plus gainers among the blue chips included International Paper, up 4 3/4 at 98; Procter & Gamble, up 4 at 91; General Electric, up 2 3/8 at 108 1/8, and Merck, up 2 1/8 at 160 5/8.

Brokers said that the market also appeared to respond favorably to President Reagan’s television address Wednesday night, in which he conceded having made a mistake in the Iran- contra arms affair.

Next on the agenda for stock traders is the government’s monthly report today on the employment situation. The figures are expected to be examined closely for signs of whether January’s weakness in economic activity carried over into February.

Gain for Chrysler

Chrysler gained 2 to 52 3/8. The company declared a 3-for-2 stock split and a dividend increase.

Engelhard, which also announced a 3-for-2 split and a higher dividend, rose 3/4 to 40 7/8.

Morton Thiokol was up 1 7/8 at 47 5/8 after trading as high as 50. The stock was added to Standard & Poor’s 500-stock composite index, a development that typically prompts buying of the issue in question by “index” funds set up to duplicate the performance of the S&P; 500.

General Host fell 2 1/8 to 11. After the close Wednesday, the company said it expects to report a loss from continuing operations for the fiscal year that ended Jan. 25.

Heck’s Inc. tumbled 2 5/8 to 4 as the company filed a petition under Chapter 11 of the federal bankruptcy law.

Advancing issues outnumbered declines by about five to four in the overall tally on the NYSE, with 874 up, 698 down and 374 unchanged. The exchange’s composite index added 1.00 to 165.41.

Large blocks of 10,000 or more shares traded on the NYSE totaled 4,289, compared to 4,292 Wednesday.

Nationwide turnover in NYSE-listed issues, including trades in those stocks on regional exchanges and in the over-the-counter market, totaled 238.45 million shares.

Standard & Poor’s index of 400 industrials rose 2.58 to 331.09, and S&P;’s 500-stock composite index added 1.92 at 290.52.

The Wilshire index of 5,000 equities closed at 2,921.866, up 6.956, or 0.58%, from Wednesday.

The NASDAQ index gained 2.26 to 429.00. The American Stock Exchange index closed at 329.47, up 3.17.

In the bond market, prices slipped Thursday as oil prices edged higher, the dollar moved lower and traders awaited February’s unemployment report.

The Treasury’s closely watched 30-year issue fell nearly point, or $2.50 per $1,000 face value. That raised its yield to 7.45% from 7.42% late Wednesday.

A slight rise in oil prices kept pressure on bond prices, according to Elliott Platt, research director for the investment firm Donaldson Lufkin & Jenrette Securities.

On the New York Mercantile Exchange, futures contracts for April delivery of West Texas Intermediate, the U.S. benchmark crude oil, rose 24 cents to $17.75 per 42-gallon barrel, extending a run-up that began last week.

Rising oil prices could foreshadow higher levels of inflation ahead, a development that would erode bond prices.

Platt said bond prices were also hurt by a decline in the dollar on foreign exchange markets. A declining dollar erodes the value of dollar-denominated holdings to foreign investors, who have been heavy buyers of Treasury bonds.

Anticipation of the unemployment report also may have kept some traders on the sidelines, analysts said.