Shares of daily deals site Groupon Inc rose more than 50 percent in their stock market debut on Friday, but at least some of the early trading exuberance may have come from the small amount of shares offered.

The shares rose as high as $31.14, or 55.7 percent above the IPO price in early trading on the Nasdaq, at one point pushing the market value of the company up to $19.9 billion. The shares later eased back to $28.36.

Groupon sells Internet coupons for everything from spa treatments to nose jobs, and is one of this year's most closely watched IPOs.

The offering, one of the largest in recent years, is an important barometer of investor appetite for IPOs. A strong first few trading days may encourage other private Internet companies, such as Angie's List, Zynga and even Facebook to pursue their own IPOs.

There is a huge backlog of companies that filed to go public earlier this year. Most plans were put on hold when the stock market slumped in August. Groupon is the first major IPO since then.

On Thursday, Groupon sold 35 million shares for $20 each, raising $700 million, but that stake amounts to only about 5 percent of the company. The dollar amount raised was on the larger side for a U.S. IPO, but it was the second-smallest offering in the U.S. in the past decade, according to capital markets data provider Ipreo.

Underwriters on the IPO were lead by Morgan Stanley, Goldman Sachs and Credit Suisse.

(Reporting by Clare Baldwin in New York, Alistair Barr in San Francisco and James Kelleher in Chicago; Editing by Derek Caney)