In addition to the FTC investigation, Facebook faces several others in the U.S. and Europe, including by the Irish Data Protection Commission, and others in Belgium and Germany. Ireland is Facebook's lead privacy regulator for Europe.
The social network said its net income was $2.43 billion, or 85 cents per share in the January-March period. That's down 51 percent from $4.99 billion, or $1.69 per share, a year earlier, largely as a result of the $3 billion charge.
Revenue grew 26 percent to $15.08 billion from a year earlier. Excluding the charge, Facebook earned $1.89 per share.
Analysts polled by FactSet expected earnings of $1.62 per share and revenue of $14.98 billion. Facebook's monthly user base grew 8 percent to 2.38 billion. Daily users grew 8 percent to 1.56 billion.