It was reported today that robotic surgery company Intuitive Surgical, Inc. (NASDAQ: ISRG) may not meet analysts average revenue expectations for 2008 and this is driving shares down $7.00 hovering around $281 per share.

Although the company guidance discussed figures around $850 million while the analysts were GUESSING $873 million temporary disappointment is affecting trading. Despite this, Eli Kammerman of Cowen & Co is maintaining his "Outperform" rating saying that he expects Intuitive to beat Wall Street expectations, and that the shares will outpace the market by 15 percent to 20 percent over the next 12 months.

So earnings might be in question, the stock is bouncing, the outperform rating is intact, and everybody still loves Intuitive -- but the stock is down so far on what is an up day. It was only a month ago I posted something similar Chasing Value: Intuitive Surgical drops on analyst disappointment after ISRG report actual earnings. If not for the analysts where would we find opportunity?

Is this a buying opportunity or signs of a week market? That answer involves more guessing, but if the stock trends down more, than it is more of an opportunity, which means you should have this world class medical device company on your watch list.

UPDATE: closing price $274.75 ,-$13.90 (-4.82%)

EXTENDED HOURS: $289.00, +14.25 (5.18%) on news that ISRG will replace Bear Stearns in the S&P 500.

Sheldon Liber is the CEO of a small private investment company and the principal for design and research at an architecture & planning firm. He writes the columns Chasing Value and Serious Money. Disclosure: I own shares of ISRG.

Shares of the online auction site eBay, Inc. (NASDAQ: EBAY) have been surging today after positive remarks from Banc of America Securities analyst Brian J. Pitz, who stated that the company is on track for a "solid" first quarter to the year.

Pitz made his remarks after analyzing the company's recent proprietary listings and conversion rate tracking data. As a result of his findings, Pitz gives the stock a price target of $38, and lifted his revenue forecast for the quarter from $2.03 billion up to $2.08 billion. This is slightly higher than the $2.06 billion that Wall Street is expecting to see, and as a result shares of the e-commerce giant have surged 5% today to $30.96, and hit a high earlier in the session up at $31.21.

eBay has been in the news a lot lately, but for the most part, it has not been positive. The company has been fighting off speculation that a seller's strike late last month that extended into the first week of March had had any material impact on the site's listing numbers. Some have argued that the strike led to a 13% drop in product listings, but eBay has adamantly denied any impact what-so-ever, and instead has insisted that a promotion that ran right before the strike had artificially inflated product listing numbers that were used to compute the strike's effectiveness.

In response to my post, "Yahoo!'s earnings message: "This is no market for investors," I received an e-mail from a Dow Jones reporter: "Hello, May I ask a question? Your headline says: "Yahoo!'s earnings message: "This is no market for investors". Provocative, but I don't see an explanation of why in your note. Could you tell me what's behind your sentiment."

Here's an answer to the question: We are in a "beat and raise" market which puts the average investor at an insurmountable disadvantage to institutional investors.

Each quarter, in order for an investor to make money, a company must beat Wall Street earnings expectations and raise guidance. Each quarter that a company actually beats and raises, Wall Street bids up the company's stock market valuation and raises its expectations for the next quarter. But eventually, the company runs up against problems that make it unable to keep beating and raising – and the stock market slams the stock. The market's reaction to Yahoo!'s earnings is a case in point.

I think the factors that would cause an investor to lose money in stocks in general outweigh the factors that would cause them to make money. The main negatives are economic trends I've cited in previous posts – rising energy prices, indebted consumers and government, declining housing market, uptick in adjustable rate mortgage payments, unpredictable new Fed Chair, global political instability. The recent performance of the S&P 500 suggests a downward trend – fueled by many of these factors.