The New York bourse saw more than double the usual trading on Potbelly Corp's shares. Bloomberg noted that this may be so due to growing investor appetite for expanding restaurant chains.

Shares closed on Friday at a 120% premium at USD30.77 a share. Potbelly's share price on Friday was the second-best trading debut on a US market exchange this year, according to Bloomberg's compiled data. The company was able to hit its USD9 to USD11 IPO pricing range target, but had to raise its price range on October 2 at a range of USD12 to USD13 due to increasing investor subscription. 

Data accumulated by Bloomberg revealed that Potbelly and its existing shareholders were able to sell 7.5 million shares at USD14 per share. The company's original terms of its prospectus indicated that it had sold 7.35 million shares, and affiliates of William Blair & Co and other shareholders sold the rest. The company at the trading close today recorded a market capitalization of USD861.8 million.