* Talks involve Comcast taking 51 pct, GE taking 49 pct
* Comcast may inject assets, up to $7 bln cash - sources
* Talks seen progressing but no deal imminent
* Other suitors face antitrust, economic challenges
* Comcast shares drop 7.2 pct, GE shares down 2.7 pct (Recasts first sentence, adds details of talks between companies, analyst comments, updates share prices)
By Anupreeta Das and Yinka Adegoke
NEW YORK, Oct 1 (Reuters) - A deal between Comcast Corp (CMCSA.O) and General Electric Co (GE.N) for NBC Universal would seem a storybook match -- one wants in to the media business and the other may be well-served to get out.
Comcast shareholders see it another way, sending its shares down 7.2 percent on Thursday as sources familiar with the matter said the top U.S. cable service provider was in talks to buy a majority stake in NBC Universal from GE.
While a deal would allow Comcast to acquire the cable networks it has coveted -- Bravo, USA and CNBC, among others -- shareholders worry it would saddle the company with more than it needs. Specifically, the underperforming NBC broadcast TV network. NBC Universal also owns a studio and theme parks.
"Investors have long pressed Comcast for an aggressive return of cash to shareholders," Bernstein Research's Craig Moffett said in a note. "An acquisition of a major content studio, even if consummated at an attractive price, is most decidedly not what Comcast investors had in mind."
GE, which has been pressured by investors to offload its 80 percent stake in NBC Universal, is considering a host of proposals for NBC Universal as partner Vivendi SA (VIV.PA) explores whether to sell its 20 percent stake.
At the moment, the most likely scenario is a deal in which Comcast would buy 51 percent of NBC Universal, leaving GE with 49 percent, according to the sources.
The sides still have plenty of details to work out and an agreement is far from certain, said the sources, who described a complex framework to discussions that are still in the earliest stages.
They said the plan is for GE to buy Vivendi's stake, and put the borrowings that fund that deal on NBC Universal's balance sheet. Other debt would also be added to what would essentially become a new, stand-alone company. But how that company would be valued remains to be seen.
One source said it would be worth $23 billion to $27 billion -- so Comcast would contribute $4 billion to $6 billion in cash and $7 billion worth of assets, like the "E" Channel and the Golf Channel, in exchange for majority control.
Another source said the new company would be valued more highly, and Comcast's cash payment would be closer to $6 billion to $7 billion.
Over time, Comcast could increase its ownership stake, according to CNBC, which first reported the news.
For GE, whose shares ended 2.7 percent lower on Thursday, selling NBC Universal would allow it to concentrate on the better-performing heavy industrial businesses. It may also be the best choice facing GE Chief Executive Jeff Immelt.
"If you take Jeff Immelt's commentary seriously, where he thinks the economy is in for a slow recovery, then the industrial side of the business needs every dollar it can keep," said Peter Sorrentino, senior vice president and portfolio manager at Huntington Asset Advisors. [ID:nN012577]
Vivendi has the right to exercise its sell option in NBC Universal each fall until 2016, but is thought likely to do so this year to fund businesses that it finds more essential.
GE could always find another buyer for NBC Universal or sell part of it through an initial public offering. But the slump in the ad market makes it a risky time to bet on media.
Antitrust issues would also make any deal with the owner of a broadcast TV network that competes with NBC nearly impossible, probably ruling out, for instance, News Corp (NWSA.O), owner of Fox, and Walt Disney Co (DIS.N), owner of ABC.
Time Warner Co (TWX.N) is one company often linked to interest in NBC Universal, but a source said it does not want the burden of the NBC network even if it wants to add more cable channels to a lineup that now includes CNN and HBO.
Cablevision Systems Corp CVC.N is expected to sell its cable networks at some stage, making it an unlikely buyer for NBC Universal. Dish Network Corp (DISH.O) and EchoStar Corp (SATS.O) were also viewed as unlikely.
Sony Corp (6758.T), Microsoft Corp (MSFT.O), AT&T Inc (T.N) and Verizon Communications Inc (VZ.N) were all mentioned by analysts -- but all were considered long shots.
For Comcast, which once failed to purchase Walt Disney Co. (DIS.N), a deal would allow it get hold of a major media company without taking on any new debt or issuing equity.
"The cable networks and the film studio hold the most obvious interest for Comcast. They're getting a relatively good valuation on their cable networks," said Chris Marangi, an analyst with shareholder Gabelli & Co. [ID:nN01262028P]
Vivendi, Comcast and GE declined to comment. (Reporting by Anupreeta Das, Yinka Adegoke and Paul Thomasch; Writing by Paul Thomasch; Additional reporting by Scott Malone in Boston and Dominique Vidalon in Paris; Editing by Derek Caney, Richard Chang and Matthew Lewis)