Yesterday, we posted our earnings press release, financial supplement, and investor presentation on selective.com's investors section. These non-GAAP measures include operating income, operating return on common equity, and adjusted book value per common share. This quarter, we delivered an operating return on equity of 13.2%, driven by strong investment income, which increased 18% year-over-year. We are on track to deliver a full-year operating ROE in the 14% range.
However, our combined ratio guidance of 97%-98% exceeds our 95% long-term target. To address this, we are prioritizing profit improvement and moderating premium growth. Second, diversifying revenue and income within and across our three insurance segments. In early September, we deployed an updated rating plan and predictive modeling to provide more granular pricing segmentation for the auto line, incorporating several enhanced variables, including additional vehicle and driver-specific criteria.
Maintaining our focus and sense of urgency is critical to improving underwriting margins and supporting long-term profitable growth. By reacting quickly to current claim trends, we are better positioned to ensure our pricing indications are appropriately positioned to achieve our long-term underwriting margin targets. Third, we continue to invest to deliver long-term profitable growth, even as the market is increasingly competitive. We also prioritize returning approximately 20%-25% of earnings through our shareholder dividend.