Take your pick. Buy Google or sell it short (a bet its stock price will fall). Either way, given the stock’s almost daily roller-coaster ride, it’s easily the most dangerous game on Wall Street, practically equivalent to swimming in shark-infested waters.

The son of one of New Jersey’s most successful businessmen can attest to the risk firsthand. He barely escaped disaster. Last year, he sold short 13,000 Google shares at around $430, the very time at which the stock of the Internet’s leading search engine was flying.

This high-risk bet turned into one of those ulcer-producing wagers as the stock subsequently ran up to an all-time high earlier this year of $475.11, meaning our short seller found himself saddled with a paper loss of nearly $6 million.

The short seller – though warned by his father he was jeopardizing his inheritance – refused to cover his short. Lo and behold, a lucky turn. Google – which went public in August 2004 at $85 a share – was subsequently bombarded by a number of rating downgrades and a disappointing fourthquarter earnings report in early February that sent the stock skidding nearly $31 a share in a single session to around $402. During the decline, our once bloodied short seller covered his position, netting a profit of about $1.3 million. The stock closed yesterday at $394.75, nearly $200 higher than its 52-week low of $224.72.

Would you believe that our fearless short-seller – to mask his true identity, let’s call him Mr. Brave – is at it again? He recently amassed a new 12,700-share short position, an attorney who knows the cast of characters told me on the condition that no names were mentioned.

Mr. Brave is hardly alone in his view that Google is a vastly overpriced stock. The latest figures show April’s short interest ballooned 67% to 7.2 million shares from 4.29 million shares the month before.

“Insane, you can get killed either way,”the veteran stockbroker Mal Lowenthal of Kern, Suslow Securities said. “I don’t know if Google is overpriced or underpriced and neither does anyone else. No one can really analyze the company because there are too many imponderables and unknowns.” His advice to clients: “You just don’t want to be there; the unpredictability factor is much too great.”

Obviously, many bullish investors disagree, with the stock generating average daily trading volume of 11,140,000 shares over the last 30 days, indicating a sizable amount of buyers.

Merrill Lynch also disagrees with Mr. Lowenthal, having just upgraded the stock from a neutral rating to a buy. It’s gung ho on Google, projecting a whopping 12-month increase of about 33% or more than $100 a share to $540.

Actually, Merrill is on the low side with that forecast. Even more ebullient brokerage predictions call for 12-month Google gains to $600, $800, and $2,000.

Whether such numbers have any legitimacy is anyone’s guess, but Merrill offers some buoyant growth projections to back up its exuberant outlook. It expects gross revenues to grow at a blistering 44% a year between 2005 and 2008. More immediately, Merrill sees 2006 revenues of $10.04 billion, versus $6.14 billion last year, and another jump to $13.9 billion next year. Giant earnings growth is also expected, with 2006 per-share earnings seen surging to $9.29 a share from last year’s $5.79. Another rise to $12.25 is projected in 2007.

Here’s part of Merrill’s rationale for upgrading the stock and forecasting such hefty numbers:

* Google’s innovation is expanding the online advertising market, conservatively expected to grow 28% this year. More than double that growth is seen by Google in America.

* Google’s products are still selling Themselves. In the first quarter, the company generated $1.53 billion in net revenues, while spending $50 million on advertising and $175 million on total sales and marketing.

* Google has big traffic assets that are under-monetized, such as new content pages like Google Finance, which seems well-positioned for branded advertising.Total American pages were up 55% year-to-year in March.

* Market share gains keep rising. Google’s Web site growth in the quarter was 97% year-to-year, compared to estimated 31% growth for Yahoo.

Given the positive factors and its expectations, Merrill figures Google’s valuation – 44 times estimated 2007 earnings and 35 times 2008 earnings – is “a reasonable price to pay” for the Internet’s revenue leader, given its projected 44% three-year growth rate.

Standard & Poor’s Google tracker, Scott Kessler, disagrees. He sees revenue deceleration this year and next year, citing among other reasons the size of Google; excessive revenue concentration (99% of sales) from just one area, Internet search advertising, and intensifying competition, especially from Microsoft and Yahoo. His stock rating: a hold, one which is generally viewed as bearish.

Mr. Lowenthal probably sums up Google investing best. “If you enjoy Russian roulette, buy the stock or sell it short. Either way, it’s a quick route to the cemetery.”

dandordan@aol.com