JAPANESE investors are learning the hard way that owning United States real estate is not a quick path to fortune.
The latest example is Mitsubishi -- majority-owner of the Rockefeller Center complex here, which filed for bankruptcy protection last week.
The Japanese have watched the value of their US holdings, which have been particularly extensive in California, Hawaii and New York City, shrink as US property values have plummeted in recent years. Plagued by financial problems at home, some Japanese firms are bailing out of US holdings at cut-rate prices.
Japanese companies' total market value losses on US real estate holdings have been ''at least $25 billion since the mid-1980s,'' reckons Dale Strickland, senior manager with Kenneth Leventhal & Company, Los Angeles, an accounting firm.
But when calculated in Japanese yen, the companies' losses have been far greater since the Japanese yen has risen sharply against the dollar in recent years.
From 1985 to 1993, Japan made some $77 billion in direct real estate investments in the US, Mr. Strickland notes.
Some of the sites were well known, such as Rockefeller Center and Pebble Beach golf course in Northern California. (Pebble Beach was subsequently sold.)
The 12-building Rockefeller Center complex here, first opened in 1932, is a well-known symbol of not only New York City commerce but one of America's wealthiest families. The center includes the 6,000-seat Radio City Music Hall, the art-deco General Electric Building. It is home to the National Broadcasting Company. And tourists come from around the world to see the giant Christmas tree set up each fall in front of a skating rink at the center.
Rockefeller Center has been controlled by Mitsubishi Estate Company, an arm of Mitsubishi Group, a Japanese conglomerate, since 1989. The Rockefeller family has maintained a 20 percent stake in the partnership. Over strenuous objections of the Rockefellers, Mitsubishi filed for bankruptcy protection for the complex, insisting it was a victim of downward spiraling real estate values.
The Rockefellers countered that Mitsubishi paid $1.4 billion for the complex, but has rung up losses of $600 million. As property values have plummeted, so too have rents, which has reduced the center's cash flow.
For the immediate future, the bankruptcy is not expected to make any appreciable difference in the way Rockefeller Center operates.
In filing for bankruptcy protection, Mitsubishi is saying that it is seeking a way ''to continue [its] support'' of a historic landmark in the US, not to somehow get out of the venture, says Michael Claes, a Mitsubishi spokesman.
Mitsubishi's difficulties underscore the hit Japanese companies and banks have taken from US investments. Aside from real estate, they have lost money on the purchase of US film studios. Sony Corporation alone took a $2.7 billion write-off for its Hollywood losses last year.
So far, only about 10 percent of the Japanese investments have been sold, says Strickland.
''A number of Japanese firms would like to get rid of their US enterprises to take advantage of new opportunities in Japan, such as construction work,'' following the recent earthquake there, Strickland says.
The problem, he says, is how. Current real estate prices, though rising in the past year, are still often well below original purchase prices.
Besides selling off US assets, Japanese firms have also sharply curtailed new purchases of US real estate. In 1993, for example, Japan invested only $710 million in US real estate, compared to over $13 billion in 1990 alone, according to Leventhal.
In addition to the US, Japan is believed to have lost billions of dollars on the value of its investments in parts of South East Asia, including Australia.
In January, Sumitomo Bank Ltd. announced it would write off some $8.1 billion in bad loans.
In doing so, Sumitomo became the first major Japanese bank to report a loss since World War II. Japanese banks are believed to hold about $450 billion in bad loans, if the loans are calculated by US banking standards, analysts say.
In the case of New York, where many buildings are owned by overseas companies, including Japanese firms, property management companies are having a difficult time maintaining high rent levels. According to Cushman & Wakefield Inc., a real estate firm, the overall vacancy rate in office buildings was almost 20 percent for New York City in April. That reflects recent contractions and consolidations in financial service firms, such as banking and securities.
Still, the office vacancy rate for the US as a whole is improving. It fell to 16.9 percent at the end of the first quarter of 1995, from 18.4 percent for the same period ending in 1995, according to Cushman & Wakefield. That's good news for real estate firms, including Japanese companies with US holdings.