Yesterday, we posted our earnings press release, financial supplement, and investor presentation on selective.com's investor section. These non-GAAP measures include operating income, operating return on common equity, and adjusted book value per common share. We are proud of our long-term track record and are taking clear steps to drive future margin improvement. In 2025, we grew book value per share by 18% and returned $182 million to shareholders through our common dividends and share repurchases at attractive valuations.
With our strong capital position, we can deploy capital in several ways that are accretive to long-term value, including continued investments to grow and diversify our business, along with opportunistic share repurchases. Net premiums written growth was 5% for the year as we executed deliberate actions to improve underwriting profitability. However, we are also executing strategies to support future growth opportunities, including expanding our geographic footprint and broadening E&S distribution capabilities with retail access. We believe we have the capabilities and strategy to further diversify our premium and outpace industry growth in coming years.
This assumption is reflected in our book results and incorporated into our 2026 guidance. This is not new, but we expect the amount of differentiation to increase. Our guidance reflects the benefits we expect in 2026 from the various actions we have taken, and our multiyear plan points to continued margin improvement in 2027. For the quarter, fully diluted EPS was $2.52, up 66% from a year ago.