• by Mark Walsh  @markfwal, March 7, 2013

Internet radio service Pandora said on Thursday that CEO Joseph Kennedy will soon leave the company.

Kennedy, who has been Pandora's CEO since July 2004, said in a statement that after discussions with Pandora's board of directors, "I reached the conclusion and advised the board that the time is right to begin a process to identify my successor."

He will remain as chief executive until a replacement is named. The announcement came just after Pandora reported fourth-quarter results that beat Wall Street expectations.

The company saw revenue rise 54% to $125.1 million on strong advertising sales for the three months ended January 31. Excluding stock-based compensation, it posted a loss of four cents a share, up from three cents in the year-earlier period.

Analysts, on average, had estimated a loss of 5 cents a share on revenue of $122.8 billion.

Pandora said ad sales in the quarter rose 54% to $109 million, while subscription and other revenue increased 74% to %16.1 million. Fueling those gains were growing usage numbers. Total listener hours grew 53% to 4.05 billion in the quarter from 2.66 billion a year ago. It had an 8% share of the total U.S. listening audience in January, up from 5.55%.

With most users now accessing Pandora via mobile, the company reported mobile revenue increased 111% to $80.3 million in the fourth quarter. That rate even outpaced mobile listener growth of 70%. The company last week imposed a 40 hour-per-month cap on free music streaming on mobile devices to help addressing rising royalty costs.

To streamline ad-buying on Pandora, the company earlier this week announced integrating its audience rating system with Strata and Mediaocean—two of the largest media buying and processing platforms. The step will let advertisers to more easily compare Pandora’s ratings alongside those of traditional radio stations.

Looking ahead, the company forecast first-quarter revenue of $120 million to $125 million, with an adjusted loss per share of between 10 cents and 13 cents.

Pandora shares were up 19% to $11.73 in after-hours trading following its announcements on earnings and Kennedy stepping down.