So how do you lose confidence on Wall Street? You can start by acknowledging sluggish sales of key products and withholding earnings guidance for the rest of the year, which is exactly what Merck ceo Dick Clark did yesterday (see the release). So far, Merck shares are down nearly 10 percent today to less than $32, a price not seen in roughly two years.

Just months after basking in the warm glow of a $4.85 billion Vioxx settlement - which inspired some investors to hail Merck’s revival - the drugmaker is suffering from difficult sales of two key products - the Singulair asthma med, which has been tied to troubling side effects, and the Gardasil HPV vaccine, which isn’t catching on as planned. And let’s not forget the ongoing woes over Vytorin and Zetia.

And so brokerages are issuing warnings. Herman Saftlas at Standard & Poor’s dropped the stock to sell from hold and lowered the target price by $16, to $29. Sanford Bernstein’s Tim Anderson cut his target by $10 to $36, although kept an “outperform” rating. Deutsche Bank’s Barbara Ryan cut her price target by 13 percent to $44.25 but kept a “buy” rating based on the low valuation and high dividend support at 4.6 percent. Credit Suisse’s Catherine Arnold dropped her price from $46 to $40.