Top commercial real estate executives across the country do not expect their industry to begin recovering from the overbuilding of the past several years until the mid-1990s at the earliest, according to a study released yesterday by Real Estate Research Corp.

In the meantime, the number of jobs throughout the commercial real estate industry nationwide -- in finance, development, brokerage and other fields -- is expected to decline by one-third to one-half, the real estate consulting and appraisal firm said. "The human toll, in terms of jobs lost, will be enormous," said Chicago-based Real Estate Research.

The annual report, sponsored by Atlanta-based Equitable Real Estate Investment Management Inc., was based on interviews with more than 100 real estate executives. It offers a glimpse of the way the industry views itself.

The executives' low expectations went beyond real estate to the economy as a whole. More than two-thirds of the executives surveyed predicted a recession next year. In the report's 12-year history, "participants have never been as bearish in their economic outlook as they are for 1991," Real Estate Research said.

Many of the executives surveyed already believe "the real estate industry is in a depression," the report said.

An oversupply of office space and a slackening demand for it have pushed developers and real estate investors into default, foreclosure or bankruptcy in many parts of the country. New construction has slowed, property values have declined and a sharp reduction in real estate lending has made it even more difficult to buy or sell commercial real estate.

Almost four out of five executives surveyed by Real Estate Research said office rents will not begin rising again until 1993, and many predicted a slower recovery. Businesses looking to lease space will be "in the catbird seat," the firm said.

The Washington real estate market, which was perceived last year as the second-most promising in the country on a Real Estate Research ranking of major cities, slipped to fourth this year, behind Seattle, San Francisco and Los Angeles. Denver was the lowest of 17 cities on the list.

The real estate industry has been through many ups and downs, but the current shakeout is not just "a business-as-usual cyclical adjustment," Real Estate Research said. Instead, it involves a lasting "structural realignment" that will produce a "stronger, more stable industry," the report said.

Developers, who historically have been the leaders of the industry, will become less important, the study predicted. Those who survive will be required to use more of their own money and less borrowed money in the future, making real estate "less entrepreneurial and less profitable."

In the past, a heavy reliance on borrowed money was the key to many quick real estate fortunes.

The real estate executives surveyed generally predicted that foreign investment in U.S. real estate will decline in 1991. Japanese investment is expected to decline by 15 percent to 50 percent, the report said. Foreign investment has already begun to shift toward Europe, where it increased to $5.5 billion last year from $3.1 billion in 1988, the report said.

Many developers have blamed their woes on a "credit crunch" that has prompted banks to pull back on real estate lending. But the Real Estate Research report described the credit crunch as good medicine. "A pickup in development activity would, frankly, be a disaster," the study said. The government agencies that have pressured banks to apply stricter standards merely forced the banks to recognize losses on real estate sooner rather than later, the report said.

The credit crunch was "welcomed by almost all of the interviewees, including those most damaged by it, the developers," the report said. "As one expressed it, 'The tougher the feds are, the faster we'll come back.' "

Gallows humor prevailed as Equitable and Real Estate Research presented their report to industry executives at a meeting at the Willard Hotel yesterday. "The difference between now and 1929 is that the windows in today's office buildings don't open," quipped Gary R. Sligar, an Equitable executive.