(VNTR) - Get Venator Materials PLC Report

seems to have an awfully bad case of stage fright.

For the third time in a week, the operator of online business-to-business exchanges has canceled a public appearance. The company backed out of a Sept. 19 presentation at a

Prudential Securities

conference in San Francisco, says Tim Getz, the Prudential analyst who covers the company. (He rates the stock an accumulate, and his firm helped underwrite the company's initial public offering.)

A Ventro spokeswoman couldn't immediately provide a reason for the company's latest cancellation. Ventro said last week that it canceled its own day for analysts because it didn't want to violate the

Securities and Exchange Commission's

new fair-disclosure guidelines, though they're not yet in effect. It also canceled its presentation at the

Robertson Stephens Internet Conference

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last week, blaming a scheduling conflict. (



wrote about Ventro's stage fright.)

Since Aug. 18, Ventro's shares have surged 53% on speculation that the company, which

disappointed analysts with its quarterly results in July, was on the block. Part of that surge came last week, when rumors spread that


( VERT) would buy the company. But VerticalNet completely

disavowed those rumors Tuesday night.

Wednesday, after VerticalNet said it wasn't in discussions to buy the company, Ventro's share fell $1.62, or 9.7%, to $15.12.