CafePress Inc.'s shares jumped in its market debut as the IPO market heats up.

The San Mateo, Calif.-based maker of personalized coffee mugs and other products is one of four companies going public Thursday and 10 this week.

CafePress priced its initial public offering at $19 a share, above the estimated range of $16 to $18 per share. The company and its shareholders sold 4.5 million shares to raise $85.5 million.

Its stock is listed on the Nasdaq Global Select Market under the symbol "PRSS". Shares rose 14 percent to $21.62 in its initial hour of trading as a public company.

CafePress joins other companies such as natural and organic food maker Annie's Inc. and mobile advertising company Millennial Media that made a big splash this week.

Millennial's shares doubled in initial trading and Annie's shares soared 89 percent in its first day of trading. Annie's represents the biggest opening day since jobs networking site LinkedIn Corp. went public in May, which closed up 109 percent in its first day of trading.

The other companies launching IPOs Thursday are manufacturer Rexnord Corp. and biopharmaceutical Merrimack Pharmaceuticals Inc. Rexnord's stock rose 10 percent, while Merrimack's dropped 9 percent.