It's Christmastime at the movie houses and showdown time for film companies

If anyone doubts the power of box-office stardom, just ask the Wall Street trading community about the Gorbachev-Reagan-Bush t^ete-`a-t^ete last week. The apparent goodwill and cordiality of the three leaders, and talk of possible Soviet troop cutbacks in Europe, gave at least a short-term boost to the stock markets. That meeting was also a reminder of the clout of ``star power,'' which seems only fitting during this year-end period when audiences at the movie houses tend to expand appreciably.

Usually, says Dennis McAlpine, an analyst with Oppenheimer & Co., the last two weeks of December are the highest-grossing weeks of the year for film companies. These companies tend to unload their most important products during this period, as they are doing now with the release of such make-or-break films as ``Scrooged,'' ``The Land Before Time,'' ``Oliver & Co.,'' ``Twins,'' ``Rainman,'' ``Naked Gun,'' ``My Stepmother Is an Alien,'' and ``Cocoon II.''

For the major studios, many of which are owned or controlled by giant conglomerates, this is showdown time on the corporate bottom line.

Industry fundamentals are currently strong, says Mr. McAlpine. During the 1987 Christmas season, about 30 films were released, six of them grossing over $30 million. Disney headed up the list last Christmas with its blockbuster ``Three Men and a Baby,'' released on its Touchstone label.

This year, McAlpine says, 23 films are being released during the holiday season. Once again, Disney is riding close to the top of the charts, with strong business from its cartoon version of ``Oliver,'' as well as ``Ernest Saves Christmas.'' McAlpine is recommending Disney as well as Gulf + Western, which owns Paramount, and Warner Communications (Warner Bros.). He says Paramount has ``two very big hits, ``Scrooged'' and ``Naked Gun.'' And Warner's ``Tequila Sunrise'' has been doing quite well.

Disney's strength - on the stock market and the box office - is based in part on its non-film earnings. In fact, a recent decision by Disney to start a new film venture has raised some eyebrows with analysts.

By the early 1990s, Disney plans to produce films through a division called Hollywood Pictures. Hollywood plans to make 12 films under that banner by 1991, thus doubling the current production under Disney's Touchstone and Walt Disney Pictures divisions. But the risk is that ``Hollywood Pictures and Touchstone will be competing for the same screens during the peak summer and Christmas periods,'' says Dennis Rosenberg, also an analyst at Oppenheimer.

Nonetheless, Mr. Rosenberg believes that by the early 1990s investors will be focusing on the opening in fiscal 1992 of Euro Disneyland, outside Paris. So unless Hollywood Pictures adds up to a box office flop, Rosenberg says, the new pictures division will probably not be very important, compared with the opening of Disney's Paris theme park.

Tucker, Anthony & R.L. Day Inc. has also been recommending Disney, putting the company in its roster of ``growth'' companies.

While liking the company on what she calls ``a short-term basis,'' Mara Balsbaugh, an analyst with Smith Barney, Harris Upham & Co., says that Disney's holiday films ``don't look commercial on a mass-appeal basis.''

She does like Gulf + Western and Warner Communications, ``but not as much as several weeks ago,'' since the market has discounted companies' major films. Warner has also been held back somewhat, she says, by the delayed merger of Warner Bros. with Lorimar, a film and television company.

One film that is expected to be a blockbuster over the next few weeks may not actually have a giant impact on its parent company, Mr. Balsbaugh says. The film is Universal's ``Twins,'' with the unlikely pairing of Arnold Schwarzenegger and Danny DeVito. ``Twins'' was brought in by Universal at a relatively low production cost. But the two stars are both expected to get a large part of the box office take - perhaps 25 to 30 percent of the gross, says Balsbaugh, who still likes the stock of Universal's parent company, MCA Inc.

MCA continues to be viewed by some analysts as a possible takeover or restructuring candidate. The company does have one other hit, Universal's ``The Land Before Time.''

Films that could be potential box office sleepers, says Balsbaugh, include ``My Stepmother Is an Alien,'' from Weintraub Entertainment Group and distributed by Columbia; ``Working Girl,'' from Fox; ``Dirty Rotten Scoundrels,'' from Orion; and ``Rainman,'' from MGM/UA. But Balsbaugh is not recommending any of those stocks.

What happens to the film companies' stocks after the holidays? Not much, McAlpine says. ``The companies, and the box office, sort of go into dormancy in early January,'' with the next checkpoint being the Academy Award period, when nominations and awards give a boost to some stocks. But after the holidays, he says, there is not much activity until the late spring or early summer, the other ``big hit'' period for the filmmakers.

Film companies, of course, were only one small part of Wall Street's focus last week. After rallying early in the week, based in large part on the Gorbachev-Reagan meeting, the market edged downward, following renewed concern that the Federal Reserve Board would boost the discount rate.

For the week ended Dec. 9, the Dow Jones industrial average closed up 51.21 points, at 2,143.49.