Facebook Inc. (FB) - Get Report shares extended declines Thursday following the release of documents to British lawmakers that suggest the social media group had offered to sell data on users' friends to select companies as late 2015 and denied other competitors access to key platform information.

The documents, which were based on high-level emails between company executives and published Wednesday by Damian Collins, a U.K. lawmaker who chairs Parliament's Culture, Media and Sports Committee, suggest Facebook used user data as a way to both grow its business and restrict rivals from stealing a march on its market dominance. Last month, Collins seized the documents from Six4Three, an app developer that is suing Facebook, after CEO Mark Zuckerberg declined to appear before his Committee's investigation into alleged Russian meddling in foreign elections. In one instance, the documents suggest, Facebook denied 'Friends' List' access to Vine, the video-sharing service, on the same day it was launched on Twitter Inc. (TWTR) - Get Report micro-blogging platform.

"The files show evidence of Facebook taking aggressive positions against apps, with the consequence that denying them access to data led to the failure of that business," Collins said. "It is clear that increasing revenues from major app developers was one of the key drivers behind the Platform 3.0 changes at Facebook. The idea of linking access to friends' data to the financial value of the developers' relationship with Facebook is a recurring feature of the documents."

Facebook shares are down 1% Thursday morning. 

"As we've said many times, Six4Three - creators of the Pikinis app - cherrypicked these documents from years ago as part of a lawsuit to force Facebook to share information on friends of the app's users," Facebook said in a blogpost Wednesday. "The set of documents, by design, tells only one side of the story and omits important context."

"We still stand by the platform changes we made in 2014/2015, which prevented people from sharing their friends' information with developers like the creators of Pikinis," the statement added.

Shares were also pressured by a downgrade from Stifel, which cut its rating on the stock to "hold" from "buy" and warned that the company's long string of negative headlines and transparency concerns could lead to regulatory restrictions and a broader exodus of users.

"We prefer Amazon (AMZN) - Get Report  Alphabet (GOOGL) - Get Report and Netflix (NFLX) - Get Report as U.S.-based mega caps with similar thematic trends and more stable operating environments," Stifel said. 

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