LOOKS LIKE we're all paying for

Tiger Woods

' sins.

$12 billion we're paying.

That's what Woods' marital infidelity has cost shareholders of various Tiger-linked stocks, from Gatorade to Gillette, American Express to AT&T, say two University of California, Davis, professors.

We'll spare you the eye-glazing details (stock nerds can do the math themselves), but basically the profs studied market fluctuations for 13 days after Tiger crashed his SUV outside his Florida home, spewing a sordid mess of infidelity that has destroyed the golf icon's reputation and cost him lucrative sponsorships.

Shareholder value on the companies studied fell 2.3 percent - or about $12 billion, with half that concentrated in three sports-related concerns - Tiger Woods PGA Tour Golf, Gatorade and Nike.

"Our analysis makes clear that while having a celebrity of Tiger Woods' stature as an endorser has undeniable upside, the downside risk is substantial, too," said Victor Stango, who did the research with fellow economics professor Christopher Knittel.

Some analysts have taken issue with Stango and Knittel's analysis, though it's hard to fault that conclusion.

Their next project, we've learned, will be a study on the market risk of using unknown economics professors in product endorsements.

Quite a yarn

Web gossipers were chortling yesterday as TMZ.com backed off its claim to have an exclusive photo of future President John F. Kennedy sunning himself on the deck of a yacht as naked babes frolicked about.

Turns out the cracked black-and-white image - which TMZ said its experts had deemed authentic - was from a November 1967 Playboy spread titled "Charter Yacht Party: How to Have a Ball on the Briny with an Able-Bodied Complement of Ship's Belles."

Those hands on deck? Definitely not JFK's.

TMZ, stick with the Hollywood foolishness you know so well, and leave the political analysis to Will Bunch's Attytood blog.

Banks cashes in

After five years on daytime TV, Tyra Banks will wrap "The Tyra Show" this spring, the former model said yesterday.

"This will be the last season of 'The Tyra Show,' " Banks, its host and executive producer, told People Magazine.

"I've been loving having fun, coming into your living rooms, bedrooms, hair salons for the past five years."

Banks wants to spend more time producing films, though she's still expected to make time for that other TV show she hosts on the CW, "America's Next Top Model."

Spike hearts Michael

Say what you will about Michael Jackson's quirky, self-destructive ways. The man created magical music, and Spike Lee has that down in his unabashedly sentimental, just-released video for the Gloved One's posthumous single, "This Is It."

What your guy wants in bed!!!

Made ya look, didn't we, girls? And so do all those hyperbolic blurbs on magazine covers. If you're up for a hearty chuckle, head to jezebel.com and click on "The Year's 10 Best Cover Lies," a mockfest of mags such as Elle, Vogue, Marie Claire - you know, the more "legit" ones you actually subscribe to, as opposed to the gossip rags you sneak-peek at in the supermarket checkout line.

Will they KISS and make up?

A couple is suing KISS front man Gene Simmons, claiming that he threatened and assaulted them at a Los Angeles mall.

Nathan Marlowe and his wife, Cynthia Manzo, also say that Simmons stole their video camera after they took pictures of him.

According to reports, Marlowe riled Simmons by asking the bassist - who's said he bedded more than 1,000 women - whether he believed in monogamy. (Gee, if he's had sex with more than 1,000 women, could the 60-year-old Simmons have time for monogamy?)

No makeup kisses here

This is the celebrity gossip column, so that means we are duty-bound to follow up on Charlie Sheen's latest mess. Briefly:

_ Prosecutors won't decide until February whether to file domestic-violence charges against the star of "Two and a Half Men," arrested Christmas Day on suspicion of menacing, second-degree assault and criminal mischief.

_ The victim hasn't been identified but is believed to be Sheen's wife, Brooke Mueller, who called 9-1-1 from their Aspen house.

According to police reports released by TMZ.com (see, this is more their kind of story), Mueller told police that Sheen held her down at knifepoint, wrapped his hands around her neck and threatened to kill her.

_ The incident is being much buzzed about in Aspen, where there have been reports of public bickering between the pair.

_ Though Sheen's supposed to be on the wagon, the phrase "alcohol-fueled" has come up a few times in descriptions of Yuletide events chez Sheen.

Christmas in Aspen? Isn't that enough to get you in a holiday mood?

Howard Gensler has the day off.

Daily News wire services contributed

to this report.