NEW YORK (

TheStreet

) -- In the world of investing, it's called being highly levered. Its when the performance of a company, and a stock, become uniquely exposed to the future of one asset. Its fiscal eggs are clumped in one basket. Its fate hangs in the balance.

Media stocks are, most than most, prone to this scenario. A show or a talent rises to cult status. Spin-offs and franchises are built. Ad revenues become tied to it. And investors increasingly come to fear its demise -- or departure.

Such is the case for the

three media stocks the we've compiled on the following pages.

Today, they may be flying high. But what of tomorrow?

Click on for their slideshows.

Sirius XM: The Stern Factor

News Corp.: Idol Worship

Viacom: MTV's Reality Reliance

SIRIUS XM:

Investors have been on the edge of their seats waiting for the word from

Sirius XM

(SIRI) - Get Report

concerning its major power player Howard Stern. As his five-year, $500 million contract with Sirius approaches its end-of-the-year expiration date, investors will stay tuned into the radio personality's plans. Whether Stern will remain at Sirius is still up in the air, but investors might be worried that CEO Karmazin might not be able to afford giving Stern a raise to keep him with the company.

Investors are especially concerned about how many of its 19.5 million subscribers Sirius XM would lose if it lost Stern. Some speculate that the company's fate hangs on the balance.

Click below for a slide show documenting Howard Stern's career and recent rumblings about his future with Sirius XM.

Sirius XM: Will Howard Stern Leave?

NEWS CORP:

For Fox, the 800-pound gorilla on its balance sheet is, of course,

American Idol

. And while parent company

News Corporation

(NWSA) - Get Report

wouldn't exactly cease to exist if

Idol

were to flop, the show certainly carries some weight -- and serves as a major platform for many of the company's cross-marketing efforts.

American Idol

is the only program in the history of television to claim the top Nielsen rating for six consecutive seasons. And as the show gears up for its tenth season and with two of the three original judges on the outs, many fear that

American Idol

won't be able to pull the same numbers it has in the past.

Click below for a slide show on the latest news surrounding the search for next season's American Idol judges.

American Idol Judges: The Latest on the Search

VIACOM:

MTV is another network that has been relying on one aspect of its programming to bring in ratings and provide parent company

Viacom

(VIA) - Get Report

with upside. As its name suggests, MTV was once known for its music television programming, but in the past years the network has increasingly moved toward car-wreck specatcle shows, along the lines of

Jersey Shore

and the

Video Music Awards

.

Viacom recently announced that

MTV had its best summer in three years

and bragged that its third-quarter ratings were up 23% year over year. The network attributed these gains to

Jersey Shore

, the summer's No. 1 show, which was No. 1 in the 12- to 34-year-old age group each week it aired. The reality show is in its second season and has just been renewed for a third season.

Click below for a slide show on MTV's reality programming.

Viacom: Counting on MTV's Shock & Awe

-- Written by Theresa McCabe in Boston.

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Disclosure: TheStreet's editorial policy prohibits staff editors and reporters from holding positions in any individual stocks.