For Facebook, the decision is part of an ongoing saga that has seen it come under fire for weak oversight of how its user data is sold to advertisers. Investors and political leaders have called for the company to break up , an insistence its founder, Mark Zuckerberg , has rejected.

S&P Dow Jones Indices announced that the social network no longer will be part of the S&P 500 ESG Index. The gauge follows companies that S&P says engage in responsible environmental, social and governance practices, a growing part of the market as investors seek out more ethical ways to put their money to work. Companies grouped as ESG-compliant have total assets of $11.6 trillion, according to an estimate from the Forum for Sustainable and Responsible Investment.

Amid ongoing controversy over its use of its users private information, Facebook has been kicked out of an index tracking companies that abide behind socially responsible practices.

In making the move, S&P cited the privacy concerns that lowered Facebook's total score used in deciding which companies will be included in the ESG Index. While Facebook received a high score in environmental issues — 82 out of a possible 100, not unusual for a tech company — its social and governance scores were much lower at 22 and 6 respectively.

S&P weights the latter two categories more heavily when it comes to tech firms.

"The specific issues resulting in these scores had to do with various privacy concerns, including a lack of transparency as to why Facebook collects and shares certain user information," Reid Steadman, global head of ESG at S&P, said in a blog post on the company site published this week that explained the move. "These events have created uncertainty about Facebook's diligence regarding privacy protection, and the effectiveness of the company risk management processes and how the company enforces them. These issues caused the company to lag behind its peers in terms of ESG performance."

The company's score has dropped consistently over the past several years.

Facebook officials did not reply to a request for comment.

Steadman noted that the index's composition is "reasonably fluid," meaning that there's always opportunity to regain standing and get back in. But he also said that Facebook has work to do.

"As Facebook's peers raise the bar in their ESG performance, Facebook will need to do even more to rejoin the ranks of the S&P 500 ESG Index," he said.

The index is up about 14% year to date, nearly in line with the performance of the broader S&P 500. Its leading constituents in terms of size include Microsoft, Apple, Johnson & Johnson, JP Morgan Chase and Amazon.

In addition to cutting Facebook, the index also dropped Wells Fargo, Oracle and IBM.