Sirius XM Holdings Inc. will acquire and Pandora Media, Inc. the largest U.S. audio streaming platform, in an all-stock transaction valued at approximately $3.5 billion.

The combination creates the world's largest audio entertainment company, with more than $7 billion in expected pro-forma revenue in 2018 and long-term growth opportunities.

This strategic transaction builds on SiriusXM's position as the leader in subscription radio and a curator of exclusive audio programming with the addition of the largest U.S. audio streaming platform. Pandora's powerful music platform will enable SiriusXM to expand its presence beyond vehicles into the home and other mobile areas. Following the completion of the transaction, there will be no immediate change in listener offerings.

The combined company will capitalize on cross-promotion opportunities between SiriusXM's base of more than 36 million subscribers across North America and 23 million-plus annual trial listeners and Pandora's more than 70 million monthly active users, which represents the largest digital audio audience in the U.S.

SiriusXM's exclusive content and programming will be combined with Pandora's ad-supported and subscription tiers to create new audio packages. SiriusXM has also extensive automotive relationships, which are expected to drive Pandora's in-car distribution.

The transaction has been unanimously approved by both the independent directors of Pandora and by the board of directors of SiriusXM.

The transaction is expected to close in the first quarter of 2019. It is subject to approval by Pandora stockholders, expiration or termination of any applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act and certain competition laws of foreign jurisdictions and other customary closing conditions.