First trading day boosts Dropbox stock

NEW YORK — Shares of the digital file storage company Dropbox soared Friday in their stock market debut.

The stock rose $7.48, or 35.6 percent, to close Friday at $28.48 in its first day of trading on Nasdaq. It had climbed as high as $31.60 during the day.

The San Francisco company offered about 26.8 million shares of stock at $21 apiece, while selling shareholders were offering about 9.2 million shares. It had expected to price the shares in a range of $18 to $20.

The company, founded 11 years ago, boasts about 500 million users. It provides services for backing up documents, photos and video.