If you follow the L.A. business scene, you probably know the answer to this question: What are the three biggest companies headquartered here?

In order, they are Walt Disney Co., Occidental Petroleum and Amgen. They’ve been the top three for years, although they tend to trade places.

But you may not know the answer to this question: Which is No. 4?

It’s DirecTV, the nation’s largest distributor of television shows by satellite. It has a market cap of about $32 billion and almost 1,700 local employees. When it signed its lease last year to occupy a three-building office park in El Segundo for 15 years, it was reportedly the largest such deal in California in the last decade. Yes, DirecTV has grown to become a surprisingly big company hereabouts.

But I’m beginning to wonder how long it’ll be such a big company. Oh, sure, it’ll be fine for several years. But eight, 10, 12 years from now? I don’t think it’ll be so big; its long-term future is a little static-y.

The existential challenge for DirecTV is the same as for other satellite and cable television providers. Customers increasingly want to migrate away from big bundled packages of TV programs and toward an a la carte system that delivers shows on the Internet.

That trend became painfully and suddenly clear last Thursday when DirecTV reported that for the first time in its history, it sustained a net loss in U.S. subscribers for the quarter. Analysts expected a loss, but the number was steeper than anticipated.

It wasn’t alone. Earlier that day, Time Warner Cable also announced a net loss of subscribers. Comcast did so a day earlier and Dish Network revealed its loss a week earlier.

I think it’s safe to say that satellite is no longer growing in the United States. The video distribution system as we know it is changing.

To their credit, satellite and cable providers have been working to keep themselves relevant. They’ve come up with better recording technologies and some are pushing broadband, for example. Significantly, Comcast bought NBC Universal to be less of a pipeline of programs and more of a creator of them.

As for DirecTV, it’s made a big move in Latin America. In fact, its increase in South American customers in the second quarter more than offset its loss in the United States. Unfortunately, that may be a delaying tactic as Internet delivery eventually will make sense to Latin Americans.

What’s more, DirecTV’s second quarter results announced last week did not include last month’s ugly nine-day blackout of Viacom-owned channels, such as MTV, Comedy Central and Nickelodeon. It’s hard to tell how many customers cut their satellite link as a result.

In fact, that brings up another problem for the cable and satellite companies. The more money the content providers demand, the more the video distributors must charge. And the more customers they’ll lose as a result.

DirecTV can complain all it wants (and perhaps correctly) that Viacom was being greedy by demanding more money, forcing home viewers to pay more. But the customer doesn’t see it that way. The customers like their programs and identify with the stars. They don’t like the satellite or cable provider. They see it as a bloodless utility that charges too much money each month and sends out repairmen who arrive at some time between 10 a.m. and 2 p.m.

The faster customers can buy individual programs directly from content creators via the Internet and eliminate the middleman, the happier the customer will be.

The Internet, as everyone now knows, is a revolutionary, historic innovation that’s creating many companies, crushing some others and permanently altering most of the rest. DirecTV, alas, is on the wrong side of that history.

DirecTV might perform well for a few more years and remain a good company for years after that, but it will never be one of L.A.’s three biggest companies. We will always need entertainment, drugs and energy. But a satellite link to feed us programs?

Well, let’s just say that it wouldn’t surprise me to see DirecTV sublet some of that El Segundo office space before its 15-year lease expires.

Charles Crumpley is editor of the Business Journal. He can be reached at [email protected].