NEW YORK ( TheStreet) -- Shares of Pandora dropped by 4.6% Wednesday, closing at $20.98, after the Oakland-based Internet radio company said it would buy Ticketfly, a ticket marketer, for $450 million. "We believe this acquisition closes the loop for Pandora by creating a one-stop-shop for artist discovery, marketing and concert ticket sales," John Egbert, a Stifel Nicolaus analyst, told the Associated Press.