Over a seven-year period ended in 1976, the number of jobs in the private sector increased by 5.7 million.

The 1,000 largest industrial corporations accounted for 74,897 of them, or 1.3 percent, according to a calculation made in 1978 by a House Small Business subcommittee. Smaller firms accounted for the rest -- 98.7 percent.

The figures call into question the impacts on job creation of the merger wave, in which an estimated $100 billion in corporate assets has been rejuggled -- mainly by big firms that have become bigger by acquiring smaller companies.

In a new study, economist David Birch of the Massachusetts Institute of Technology has found that employment in firms acquired in mergers grew at somewhat lesser rates than in similar independent companies.

"Historically, small business has created the bulk of new jobs," William K. Eastham, board chairman of the U.S. Chamber of Commerce, told the subcommittee. "If problems of employment are to be resolved, it is likely that we must depend on small business as a principal factor in the solution."

Harold M. Williams, chairman of the Securities and Exchange Commission, says pointedly that the estimated $100 billion spent in the merger wave, now in its sixth year, could have been but was not "devoted to new production and employment opportunities."