Pandora Media Inc., the biggest online radio service, forecast lower third-quarter profit than analysts had estimated as the company adds to its sales staff. The shares fell in aftermarket trading.

Adjusted profit for the current period will be 3 cents to 6 cents a share, below the 8-cent average of analysts’ estimate, the Oakland, California-based Pandora said Thursday in a statement. For the full year, results will range from breakeven to profit of 5 cents excluding items. Analysts had estimated 5 cents.

Pandora had 71.2 million active listeners in July.

Its shares rose 1 percent to $21.71 in regular trading Wednesday, but were down 4.7 percent at $20.69 in extended trading shortly after 5 p.m. New York time.