UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ Quarterly report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the Quarterly Period Ended: March 31, 2024 ☐ Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Commission File Number: 001-15891 NRG Energy, Inc. (Exact name of registrant as specified in its charter) Delaware 41-1724239 (State or other jurisdiction (I.R.S. Employer of incorporation or organizati ...