Short sellers are apparentlyrunning the market for China stocks. But it ain't what they say so much as the fact they say it that has investors hitting the 'sell' button. With a market this vulnerable, investors must question the rationale for holding any but the bluest-chip overseas-listed Chinese companies.

The latest stock to fall under the short sellers' sword belongs to Nasdaq-listed advertising display firm Focus Media Holding Ltd. After short seller Muddy Waters alleged accounting shenanigans, the Shanghai-based company's shares fell 60% in an hour