Riverbed Technology Inc. (Nasdaq: RVBD) staged a stunning debut on Nasdaq Thursday, listing at $9.75 per share and then leaping by $4.56, nearly 47 percent, in its first few hours of trading.

The WAN optimization company's IPO of 8.7 million shares, plus a further 100,000 shares sold by an existing stockholder, raised $85.8 million, with Riverbed pocketing $76 million after the underwriter discount and expenses.

The company will be in line for further proceeds if the underwriters, led by Goldman Sachs & Co. , take up their 30-day option to purchase a further 1.3 million shares.

With about 13.6 percent of its shares now trading publicly, the initial listing price of $9.75 -- which was above the initial stated range of between $7 and $8.50 -- valued the company at $631 million. It's current share price, though, values the company at $927 million. (See Riverbed Sets IPO Terms.)

Riverbed has experienced massive growth this year. Its revenues in the six months to June 30 were $31.8 million, up from $5.2 million in the same period a year earlier, while its customer base has grown from 500 in January this year to more than 1,000 at the end of June.

— Ray Le Maistre, International News Editor, Light Reading