The stock market was broadly lower in early trading today, pressured by ongoing concerns about this week's Treasury's refunding. The Dow Jones average of 30 industrials was down 20.27 points to 2,586.04 at 10 a.m. EST, 30 minutes after the opening bell. Declining issues outnumbered advancers by a margin of nearly 5 to 1 on the New York Stock Exchange, with 835 issues down, 178 up and 378 unchanged. Volume on the Big Board came to 24.08 million shares. Analysts said weakness in the bond market kept stocks under pressure. The market's worries stem from the Treasury's quarterly refunding auction and whether yields will have to be forced higher to attract Japanese investors. The three-day auction, which began on Tuesday, comprises $30 billion in notes and bonds. Tuesday's refunding included $10 billion of three-year notes. Today's refunding will include $10 billion in 10-year notes and the final part on Thursday will comprise $10 billion of 30-year Treasury bonds. The NYSE's composite index of all its listed common stocks was down 1.47 at 180.86. At the American Stock Exchange, the market value index stood at 354.01, down 0.73. Among actively traded issues on the NYSE, Harcourt Brace was down &lsqb; to 2, Pan Am was off &lsqb; to 3{, AT&T was down { to 39 and American Express had slipped { to 28}. Among the Big Board gainers, Baxter International was up &lsqb; to 23&rsqb;, IBM had gained &lsqb; to 101&lsqb; and Hong Kong Telephone had advanced \ to 20. On Tuesday, the Dow Jones industrial average fell 16.21 to 2,606.31. Declining issues outnumbered gainers by about 3 to 2 in nationwide trading of New York Stock Exchange-listed stocks, with 578 up, 909 down and 499 unchanged. Volume on the floor of the Big Board came to 134.07 million shares, only slightly ahead of the 130.95 million shares traded on Monday in the slowest session to date in the new year.