Neptune Insurance Holdings Inc's stock surged 23.58% in pre-market trading on Thursday. The significant move followed the company's release of its fourth-quarter financial results, which exceeded market expectations.

The flood insurance provider reported Q4 revenue of $43.8 million, surpassing analysts' average estimate of $39.48 million. The company attributed this revenue growth to continued strength in its primary residential flood insurance business and the expansion of its distribution partnerships. Its adjusted earnings per share for the quarter came in at 10 cents, meeting market expectations.

Following the earnings report, Keefe Bruyette upgraded Neptune Insurance's rating to Outperform from Market Perform, citing the Q4 performance. The positive earnings surprise and the subsequent analyst endorsement are the primary drivers behind the stock's sharp pre-market appreciation.