Pandora, the biggest online radio provider, fell the most in almost six months after reports Apple aims to unveil a competing service as early as next week.

Pandora fell 11 percent to $15.22 at the close in New York, the biggest one-day decline since Dec. 5. The Oakland, Calif.-based company’s stock had almost doubled this year through May 31.

Apple is pressing to sign music-licensing deals in time to announce its iRadio service at its annual developer conference starting June 10 in San Francisco.