Shares of Houghton Mifflin Harcourt Co , a textbook publisher that emerged from bankruptcy last year, rose as much as 33 percent in their market debut, valuing the company at about $2.23 billion.

The company's shares opened at $14 and touched a high of $15.96 on the Nasdaq on Thursday.

A total of 18.3 million shares were sold in the offering, all of which came from selling stockholders including hedge fund billionaire John Paulson, the company's biggest stockholder with a 23 percent stake.

Other big shareholders who sold include Anchorage Funds, Avenue Capital Management II LP and BlackRock Funds.

The offering was priced at $12 per share on Wednesday, below its expected price range of $14-$16.

"They found the right level of price to attract investors and it has a nice little pop," said John Fitzgibbon, founder of IPO tracking website Iposcoop.com.

Houghton Mifflin also publishes the "Curious George" and J.R.R. Tolkien's "Lord of the Rings" book series, and games such as "Where in the World is Carmen Sandiego?"

The company, which has been publishing books since 1832, emerged from bankruptcy in 2012 after bondholders holding about $3 billion in debt received equity in the company.

Houghton's debt troubles started in 2006, when Education Media & Publishing Group Ltd borrowed heavily to buy it from Thomas H. Lee Partners and Bain Capital for $1.75 billion. The Dublin-based group later merged Houghton with Harcourt, which it bought from Reed Elsevier Plc for about $4 billion.

Boston-based Houghton Mifflin Harcourt, whose rivals include Pearson Education Inc, McGraw Hill Education and Scholastic Corp, is headed by 60-year-old Linda Zecher. She most recently served as corporate vice president at Microsoft Corp.

Textbook publishers have struggled as more readers go online for information. Some have tried to make headway into digital learning programs, but other factors have also hamstrung the industry including spending reductions by state and local governments and the growth of the used book and book rental markets.

Scholastic Corp is up marginally this year, while the publisher of the "For Dummies" books John Wiley & Sons Inc is up about 26 percent.

Shares of textbook rental company Chegg Inc slumped about 20 percent in their trading debut on Wednesday.

Houghton Mifflin's loss narrowed to $46.5 million for the nine months ended Sept. 30, from $52.9 million a year earlier. Revenue rose about 8 percent to $1.07 billion during the same period.

Goldman Sachs and Morgan Stanley were the lead underwriters of the offering.