In its second day as a publicly traded company, Blackstone Group co-founder Stephen Schwarzman lost $655 million on his shares as Wall Street cooled to his deal.

Despite a gain of 13 percent on its debut on Friday, shares tumbled yesterday by 7.5 percent, wiping out nearly half of its opening day advance.

In relative slow trading of about 36 million shares – compared with an opening day buying surge of 113 million shares – Blackstone fell $2.62 to $32.44 from its opening day close of $35.06.

In early afternoon trading as talk in Washington intensified on a bill to double the taxes on Blackstone’s investors, shares dipped as low as $31.90, just 90 cents higher than its original price of $31.

“I think the anesthesia has worn off with some investors,” said David Menlow, president of IPOfinancial.com. “Some felt [Blackstone] was a must own and I still agree that is the case, but it is a question of valuation.”