The stock market forged ahead Friday, extending its advance to record highs as Wall Street experimented with new procedures designed to smooth out the quarterly "triple witching hour."
The Dow Jones average of 30 industrials rose 12.72 to 2,420.85, bringing its gain for the week to 43.12 points.
Volume on the New York Stock Exchange reached 220.48 million shares, up from 168.58 million Thursday.
It was the first time that contracts and a few other stock-index futures and options were settled as of the opening on expiration Friday, rather than the close.
The new procedure appeared to go smoothly, with no dramatic price swings in the market.
A second settlement period at the close for several other stock-index contracts went just as uneventfully.
Merck Big Gainer
Merck was the biggest contributor to the Dow Jones industrial average's gain, rising 3 3/8 to 165 3/4 on interest in a cholesterol-reducing drug being developed by the company.
Advancing issues outnumbered declines by more than three to two on the NYSE. The exchange's composite index gained 0.73 to 172.57.
The NASDAQ composite index for the over-the-counter market edged up 0.11 to 429.08. At the American Stock Exchange, the market-value index closed at 339.90, up 1.26.
In the credit markets, bond prices were slightly higher after closely following the dollar throughout a lackluster session.
The Treasury's 30-year bond was up 5/32 point, or about $1.50 for every $1,000 in face amount. The bond's yield, which moves inversely to its price, edged down to 8.47% from 8.48% Thursday.
In corporate trading, industrial issues rose 1/8 point and utility bonds were unchanged in light trading.
Among tax-exempt issues, general obligations fell 1/8 point and revenue bonds rose 1/8 point in light trading. Yields on three-month Treasury bills were up one basis point at 5.65%. Six-month bills rose 4 basis points to 5.92%. One-year bills fell 1 basis point to 6.28%.
The federal funds rate, the interest on overnight loans between banks, traded at 6.69%, down from 6.75% Thursday.