Of all stocks that have made Mexico's Carlos Slim Helu the world's richest man, New York Times Co. (NYSE: NYT) may be the best known.

And that's saying something. Slim is better known for investing in civil infrastructure such as the energy and telecom sectors than he is media. His biggest holdings include America Movil (NYSE: AMX), Saks, and Philip Morris International (NYSE: PM).

Yet, last January, Slim spent $250 million of his estimated $53.5 billion fortune to acquire warrants with the right to buy 15.9 million class A shares of New York Times at $6.3572 each. Fortunately for Slim, the stock is up more than 80% since.

But wait, it gets even better. New York Times also agreed to pay Slim an annual 14.053% coupon rate on his investment. How impressive is that? For comparison, in the height of the financial panic, Warren Buffett managed to extract just 10% in annual dividend payments from General Electric and Goldman Sachs (NYSE: GS).

This track record is just one of the reasons why I listen when Slim speaks, especially if he has something to say about New York Times -- a stock I bought and then dumped after speculators handed me a 50% return in a matter of months.

What's Slim saying now? Nothing, actually, but a spokesperson recently denied a rumor that the billionaire would buy New York Times Co. outright. "There is no change (in the stake holding)," Slim's chief spokesman, Arturo Elias, told Reuters. "For the time being, we are very happy with the company's performance."

Is this gamesmanship, a mistake, or savvy investing on Slim's part? Let's dig into both the bull and bear arguments for New York Times Co.

The bull argument
Buyers will tell you that New York Times is the top dog in an ailing industry, and that history shows the bare-knuckles performers in bad businesses can make for outstanding investments. Just ask anyone who's owned shares of Nucor over the past decade.

"This might be a case of picking the best house in a bad neighborhood. I like that they are cutting jobs at the New York Times and playing hardball with The Boston Globe ... I don't think that [The Times] will find a way to save journalism. I just think that they will manage their decline better than the others," wrote All-Star investor WPThatcher in an October pitch in Motley Fool CAPS.

New York Times Co. has worked out a labor deal with union workers at the Globe, and in February the company reported an 11% improvement in fourth-quarter operating profit thanks to aggressive cost-cutting, including $290 million worth of debt reduction. Even circulation revenue improved, up 2%. The Times is clearly making progress.

Apple's (Nasdaq: AAPL) iPad makes the story even more compelling. According to new research, readers who browse newspapers' online editions spend anywhere from 70 seconds to three minutes and four seconds per day at their favorite sites. By contrast, subscribers to a newspaper's print edition spend an average of 25 minutes per day with their favorite rag.

That's a massive gap. If the iPad and other e-readers encourage consumers to buy digital subscriptions for these new devices, it could boost subscriber engagement and perhaps even circulation over the very long term. Either way, it creates a brand new revenue opportunity for New York Times Co. that, due to the low costs of Web distribution, could enjoy healthy margins.

The bear argument
Of course, the key word to the entire bull argument is "if." Consider what we already know. New York Times Co. saw declining print and digital revenue during 2009, and online newspaper advertising fell for the first time in 2008, according to new research from the Newspaper Association of America.

Meanwhile, for as much as we'd love to believe the iPad will save the New York Times and boost other ailing publishers like Gannett (NYSE: GCI) and News Corp. (Nasdaq: NWS), Wall Street isn't optimistic that the company will be able to transform higher revenue, if it comes, into dramatically higher profit. On average, analysts project 3.5% profit growth per year over the next five years, according to Standard & Poor's Capital IQ.

The range of opinions may tell more than the average, though. Optimists call for The Times to boost income by 12% a year; pessimists expect a 5% annual decline. The message? Opinions vary about the size and impact of New York Times' digital opportunity.

As a member of our Motley Fool Rule Breakers team, I'd tell you that uncertainty is acceptable -- especially when it comes to emerging technology. History has given us enough examples to rationally project tech outcomes.

The problem here is that the newspaper industry is neither tech-centered nor emerging. Investors' only logical move is to demand a steep discount before buying shares of New York Times Co., yet the stock trades for roughly 20 times normalized earnings. That's far too expensive a multiple for such a speculative media play.

Recommendation: don't buy
Slim's silence makes sense when you run the numbers. The iPad might prove to be a massive winner, and pull up the Gray Lady by her bootstraps in the process, but with the stock trading for far more than Wall Street's most optimistic growth projections, investors aren't being compensated enough to gamble.

Would you buy New York Times Co. at these levels? What price would it have to trade at for you to be willing to make a purchase? Share your thoughts using the comments box below.