The ranks of “super-investors” are few, highlighted by the likes of Warren Buffett, George Soros and Carl Icahn. Investors like to track their every move.

Smart investors should also watch the moves of David Einhorn, who runs Greenlight Capital. He started with just $1 million in 1996, has made more than +20% a year for his clients, and now manages billions. He’s made his name on some high-profile short sales such as Lehman Brothers and Allied Capital (NYSE: AFC). But he’s also done quite well on the long side of his portfolio. That’s why I review his latest holdings to see what he’s buying and selling. In his latest mandated 13-F filing, Einhorn is loading up on two stocks that trade below book value. Here’s why.

Ingram Micro (NYSE: IM)
Ingram is the world’s largest distributor of computers, printers, scanners, copiers and other tech products, with operations across the globe. It’s not a sexy business, but it sure is profitable. During the past three years, Ingram has generated nearly $1 billion in cumulative free cash — right at a time when the economy has been pretty lousy. With recent tweaks to the business, management believes that annual free cash flow could exceed $500 million if global sales rise at a moderate pace.

All that cash flow has created a balance sheet on steroids, as gross cash now stands at more than $1 billion and tangible book value sits at $19.18 a share — nearly +10% above the current stock price. If the company can indeed generate $500 million in annual cash flow in coming years, then book value per share would rise about $3 a share every year, creating annual returns of nearly +20%.

#-ad_banner-#To be sure, Einhorn, who just bought more than $300 million of Ingram’s stock, isn’t looking for swing-for-the fences returns. Shares are unlikely to move up past the $23 to $25 mark even in a better economy. So this stock may only have +25% to +35% upside during the next few years. But that potential upside is matched by very limited downside thanks to that rock-solid balance sheet.

Trans-Atlantic Holdings (NYSE: TRH)
Companies that are in the business of providing insurance to other insurers (known as re-insurers) need to keep lots of cash on hand in case clients need them to pay up. But this firm, with $13.3 billion on hand, may be carrying too much cash. After all, potential liabilities are less than $10 billion. How did the company get so much cash? By generating at least $600 million in free cash flow in each of the past seven years.

And with all that cash gaining almost no interest, Trans-Atlantic has no choice but to pay out dividends (which offer a paltry 1.6% yield) or buy back stock. Trans-Atlantic is focusing on the latter, having just announced another $200 million buyback program. And as the share count keeps shrinking, per share profits rise. Analysts expect this re-insurer to earn more than $6 a share in 2011, and shares trade for about eight times that forecast.

But Mr. Einhorn is likely here for the balance sheet, not the income statement. Trans-Atlantic carries $4.3 billion in shareholder’s equity, well ahead of the company’s $3.2 billion market value. (Said another way, the stock trades for just 74% of a book value of $69 a share.) As an added kicker, if and when interest rates start to rise, all of that sidelined cash will generate hefty streams of interest income.

Action to Take –> Mr. Einhorn is known for some high-profile aggressive bets, but some of his more low-key plays such as Ingram Micro and Trans-Atlantic Holdings are equally intriguing. Neither is likely to make you rich, but they look like solid “safe” plays with nice upside.

P.S. — There’s an analyst with a track record you need to see. She has an 89% win rate — remarkable for this market. And she just keeps picking winners. One of her recent picks shot up +18.2% in just 13 days. Go here for the details…