Pandora Media (P) wants to be more things to more people without damaging the core of its business: ad-supported Internet radio.

In recent weeks, the Oakland-based Internet radio provider has purchased a concert ticketing business, jumped headfirst into podcasting, and most recently, acquired the infrastructure to launch an on-demand music streaming business to compete directly with SpotifyApple (AAPL - Get Report) Music and Alphabet's (GOOGL - Get Report) YouTube, which earlier this month introduced its own subscription platform.

But Pandora shares were slipping Tuesday in the wake of the company's move to acquire rival music streaming service Rdio's technology and intellectual property for $75 million. Rdio, which is filing for bankruptcy, offers both an ad-supported and an ad-free subscription service that allows users to select the songs they want to hear. Rather than purchasing subscribers to Rdio, Pandora will acquire the infrastructure and employees to help it build an on-demand music service.

Whether that means something similar to Spotfiy or Apple Music, CEO Brian McAndrews wouldn't say when speaking with investors on a conference call on Monday. But judging from Pandora's recent deal to become the exclusive streaming partner of the podcast Serial and the public radio show This American Life, as well as its purchase of the concert ticket site Ticketfly, the customized radio provider clearly wants to offer its user base of 78 million people more services, and more ways to spend their money.

"If Pandora can educate those roughly 80 million users on the value of a subscription, you could see some really dynamic revenue growth -- but that's going to take some time,"  said Russ Krupnick of the consumer research consultancy Music Watch. "All of these platforms, whether Pandora or Spotify, are going to have to evolve, which might mean getting into video, news and sports, and talk."

As the only publicly traded standalone music-streaming service, Pandora is closely watched. And on Tuesday, investors appeared skeptical or impatient, given that McAndrews said the Rdio deal is unlikely to contribute to sales until the second half of 2016, or later.

Pandora tumbled 35% on Oct. 23 after forecasting that revenue in the current quarter would total between $325 million and $330 million, short of the $351 million projected by analysts surveyed by Bloomberg. Since then, Pandora had been on a modest rebound, gaining 8%. But that mild resurgence was trimmed on Tuesday, with shares falling another 5.4% to $12.69.

"While we expect Pandora will benefit from some synergies, we believe the deal is more about jump-starting an on-demand service, and their strategy than maximizing deal synergies," said Amy Yong, a media analyst at Macquarie, who rates the shares comparable to a buy. "We remain constructive on Pandora's ability to monetize its user base and show that their business model has long-term sustainability."

That business model is likely to remain ad-supported, an area that neither Spotify nor Apple have signaled any interest in entering. Pandora does have 3.9 million subscribers who pay $5 a month for Pandora One, its ad-free service. But both products are customized radio rather than on-demand streaming.

For Pandora, the Rdio deal could allow it to brand outside of the U.S., which remains home to the great majority of its listeners. Rdio says it's present in some 85 countries.

Pandora may also be interested in some of the features that Rdio popularized on its music service, such as a networking component that allows users to share songs and playlists via social media platforms.

"Rdio has had some really great engineers over the years, it could be that there were some engineering features that Pandora wants to enhance its Internet radio," added Krupnick, whose Music Watch counts Pandora among its clients.

The 11-year old Pandora has been slow to get into on-demand Internet music, choosing instead to differentiate itself as a music aggregator. Users select an artist, and then Pandora plays them similar songs. Each customized radio station can be further refined by adding additional artists.

That aggregator radio model has largely worked to build a loyal audience. Pandora users spend some 22 hours a month on the service, McAndrews said.

Still, Apple's entrance into music streaming has raised the bar for Pandora, even though its listener hours in the third quarter totaled 5.14 billion, a 3% increase from the same period a year earlier though at a slower pace than in previous quarters. Apple's heavily marketed streaming service was blamed in part for Pandora's lower than expected sales forecast for the fourth quarter.

Rdio could offer Pandora a means to improve its relations with music labels, which remain in a bitter dispute with the company over royalties. While Pandora did succeed in winning a favorable initial ruling from the U.S. Copyright Royalty Board in September, a final decision on a payment scale for streaming music remains a wild card for the business and an overhang on the stock.

"There has been a lot of friction between Pandora and the labels and artist community, and this may help them mitigate it," Krupnick said.

The board is expected to make a final ruling sometime next month.