Shares of Rubicon Project Inc. on Wednesday rose more than a third in its New York Stock Exchange debut.

The Playa Vista online advertising exchange raised $102 million in a modestly priced initial public offering. The company sold 8 million shares priced at $15 a share, the low end of its earlier projected range. The company itself will receive about $81.3 million in proceeds from the 5.4 million shares it sold. The remaining shares were sold by longtime Rubicon backers.

Rubicon operates a digital ad exchange that automates the sales and placement of online advertising. Chief Executive Frank Addante is the largest individual shareholder, with a 10 percent stake. Clearstone Ventures owns 21 percent of the company, followed by News Corp. with 19 percent and Mayfield Fund with 14 percent.

Underwriters, led by Morgan Stanley, Goldman Sachs and RBC Capital Markets, have a 30-day option to purchase up to an additional 1.02 million shares.

Shares closed up $5.09, or 34 percent to $20.09.