EchoStar Communications Corporation, the No. 2 satellite provider, whose chief financial backers include Mr. Murdoch, makes more money selling graphic adult films through its satellite subsidiary than Playboy, the oldest and best-known company in the sex business, does with its magazine, cable and Internet businesses combined, according to public and private revenue accounts by the companies.

AT&T Corporation, the nation's biggest communications company, offers a hard-core sex channel called the Hot Network to subscribers to its broadband cable service. It also owns a company that sells sex videos to nearly a million hotel rooms. Nearly one in five of AT&T's broadband cable customers pays an average of $10 a film to see what the distributor calls ''real, live all-American sex -- not simulated by actors.''

For all the money being made on sex -- legally -- by mainstream corporations, the topic remains taboo outside the boardroom. The major satellite and cable companies do very little marketing of their X-rated products, and they are not mentioned in annual reports except in the vaguest of euphemisms.

None of the corporate leaders of AT&T, Time Warner, General Motors, EchoStar, Liberty Media, Marriott International, Hilton, On Command, LodgeNet Entertainment or the News Corporation -- all companies that have a big financial stake in adult films and that are held by millions of shareholders -- were willing to speak publicly about the sex side of their businesses.

''How can we?'' said an official at AT&T. ''It's the crazy aunt in the attic. Everyone knows she's there, but you can't say anything about it.''

For hotels, the sex that can be piped through television generates far more money than the beer, wine and snacks sold from the rooms' mini-bars. Just under 1.5 million hotel rooms, or about 40 percent of all hotel rooms in the nation, are equipped with television boxes that sell the kind of films that used to be seen mostly in adults-only theaters, according to the two leading companies in the business. Based on estimates provided by the hotel industry, at least half of all guests buy these adult movies, which means that pay-per-view sex from television hotel rooms may generate about $190 million a year in sales.

At home, Americans buy or rent more than $4 billion a year worth of graphic sex videos from retail outlets and spend an additional $800 million on less explicit sexual films -- all told, about 32 percent of the business for general-interest video retailers that carry adult topics, according to compilations done by two trade organizations that track video rentals. Chains like Tower Records now stock nearly 500 titles in their so-called erotic category, far more than films about history or dinosaurs.