GALVESTON, TX — American National Insurance Company (Nasdaq: ANAT) announced net income of $18.8 million or $0.70 per diluted share for the first quarter of 2018. Net income for the first quarter of 2018 was reduced by $25.7 million in unrealized losses on equity securities as a result of our adoption of new accounting guidance1 which impacted the first quarter of 2018 but not the first quarter of 2017. Excluding the impact of these unrealized losses, net income would have been $44.5 million or $1.66 per diluted share as compared to first quarter 2017 net income of $39.8 million or $1.48 per diluted share.
Operating income for the first quarter of 2018 increased to $44.1 million or $1.63 per diluted share compared to $28.3 million or $1.05 per diluted share for the same period of 2017. Operating income for the quarter primarily increased as a result of improved earnings from our property and casualty segment due to a lower combined ratio in the first quarter of 2018 as compared to the same period in 2017. Operating income excludes net unrealized gains (losses) on equity securities and realized investment earnings. Realized investment earnings are comprised of realized investment gains (losses), equity in earnings (losses) of unconsolidated affiliates and income (loss) from non-controlling interests.
Book value per diluted share was $194.37 as of March 31, 2018 consistent with book value per share of $194.61 on December 31, 2017.
After-tax realized investment earnings for the first quarter of 2018 were $0.4 million or $0.03 per diluted share compared to earnings of $11.5 million or $0.43 per diluted share for the same period in 2017.