It's hard to ignore any investment actions taken by the world's richest man, or any entity associated with him for that matter, so when the Bill & Melinda Gates Foundation recently announced that it had taken an interest in homebuilding companies, the news caught the attention of Bernie Schaeffer, the editor of The Option Advisor.

In particular, Bernie is intrigued by Centex (NYSE: CTX), which the Gates' disclosed as one of those homebuilders in which it had invested. And while that hat news led to a quick gain of 4% in the shares, Schaeffer remains bullish.

He explains, "Technically, the stock vaulted it back above support at its 10-week moving average. In conjunction with its 20-week counterpart, these trend lines have provided support for CTX since the middle of August. The stock has additional support at its rising 50-month moving average, which it has not closed a month below since July 2000."

Despite its strong technical position, the contrarian analyst notes that pessimism – based on put and call buying by speculators - is still prevalent on CTX. Further, he adds, nearly 10% of the stock's float is sold short, and this, he says, "creates fuel for a short-covering rally."

Finally, he adds that six of the 11 Wall Street analysts following CTX rate it a 'hold' or worse, which he adds, is "creating the potential for upgrades that could increase buying pressure."

While following the Gates' interest in homebuilders intrigues Bernie, he is less optimistic about the company that was the foundation for the Gates Foundation - Microsoft Corp. (NASDAQ: MSFT). Technically, he notes that while the stock has had a run higher recently, the shares have rallied into long-term resistance at the round-number 30 level.

He also observes the this level region "has stonewalled MSFT on a monthly basis since March 2002. In addition, he points out that the 30 region is half of the stock's all-time high of 59.96 – which adds additional strength to the resistance.

What's more, he notes, a "whopping 650,000 calls reside at the 30 strike in the front three months of options, creating quite a hurdle of potential options-related resistance."

Further from a sentiment standpoint, he notes that the shares have little short-covering support to halt a decline. He notes that it would take under two days to buy back all the MSFT shares sold short at the stock's average daily trading volume.

Finally, he notes that Wall Street analysts are is still "enamored of the equity, with 13 of the 19 analysts following MSFT rating the stock a 'buy' or better," which from his view increases the chances of potential downgrades.

For those aware of the risks inherent in buy options, I'd add that Schaeffer is recommending the Centex April 45 calls to benefit from his bullish outlook for the homebuilder, while also recommending Microsoft January 2008 35 puts, based on his bearish outlook for the software giant.

Steven Halpern is the editor of TheStockAdvisors, a free daily overview of the latest stock picks from the financial newsletter community.