Facebook Inc., the social network, has agreed to pay a $3.9 billion civil penalty and pay $8.5 billion in fines for defrauding investors and violating securities laws, the U.S. Securities and Exchange Commission said in a filing Thursday.

The fine covers Facebook’s alleged mispricing of its mobile payments business and failed to disclose the price of the social networking company’s shares, which it failed to pay for nearly three years, SEC Chairman Jay Clayton said.

Facebook did not disclose the total value of the fraud, Clayton said in the filing.

The SEC also alleged that Facebook failed to take measures to prevent the spread of the breach, including a failure to investigate potential security risks.

Facebook did not immediately respond to a request for comment.

Facebook announced in August that it would pay $1 billion in a settlement with the SEC, which accused the social media company of misprices of its Mobile Payments business and a failure not to disclose that the price the company paid for its shares of its stock was $3,500 higher than the fair value of its shares.

The SEC also accused Facebook of failing to take steps to prevent potential security threats, including failing to investigate and mitigate those risks and failing to notify investors that it was failing to protect the information it was storing on its computers.