The inland marine line of insurance coverage continues to outperform the broader U.S. property/casualty (P/C) sector on underwriting performance, according to a new report by AM Best. The segment’s specialized expertise in covering goods transported across land and inventory stored at temporary off-site locations has fueled consistent profitability, even as premium growth remains limited and largely driven by inflationary factors and ancillary coverages.

Underwriting Performance

Inland marine underwriters have consistently reported lower calendar year loss and loss adjustment expense (LAE) ratios than the broader P/C industry across all lines underwritten. This performance gap has expanded to greater than 20 percentage points annually over the past four years.

Christopher Graham, senior industry analyst at AM Best, noted that the line’s underwriting performance reached an eleven-year low for loss and LAE ratios in 2025. This metric highlights the segment’s ability to maintain tight control over claims costs despite evolving risk landscapes.

Market Dynamics and Exposure

The inland marine coverage line includes on-site materials for construction projects and special high-value items such as fine arts, computers, television, video and sound equipment, and medical diagnostic equipment. Historically, there has been an 80/20 split between commercial inland marine exposures (such as freight or property on the move) and personal inland marine exposures (including high-value niche items like fine arts, jewelry, and collectibles). Pet insurance was included in this coverage line up until 2024.

Construction spending serves as a proxy for the number of exposures or property being insured. U.S. construction spending overall has fallen slightly since its peak in 2024. Less construction spending could mean less demand for inland marine insurance, potentially causing increased competition and pricing cuts for projects that do get moving.

Competitive Landscape

The report notes an increasingly competitive inland marine landscape over the past decade, with top insurers holding less market share now than five years ago. A small increase in concentration among the different groupings within the segment’s top 10 ranking in 2024 was attributed to pet insurance plans becoming their own line rather than any actual market share increase among the top carriers.

What the Numbers Show

The divergence between the segment’s underwriting discipline and broader market pressures is evident in the data. While the top insurers have seen their market share erode over the last five years, the segment’s collective loss ratio gap against the wider P/C industry has widened to more than 20 percentage points annually. This suggests that profitability in inland marine is driven less by market dominance or volume growth and more by specialized risk selection and claims management capabilities that remain effective even in a fragmented competitive environment.

AM Best will host a complimentary webinar titled 'Inside Today’s Surplus Lines Market' on Wednesday, September 16, 2026, at 11:00 am EDT. The one-hour session, sponsored by the WSIA Education Foundation, will feature a panel of industry leaders reviewing the U.S. surplus lines insurance sector alongside highlights from a new report.

Panelists and Agenda

The webinar will include insights from five key figures in the insurance industry:

• Patrick Albrecht, president, Associated Insurance Administrators
• Brady Kelley, chief executive officer & president, WSIA Education Foundation
• David Nelson, executive vice president – wholesale, Nationwide E&S/Specialty
• Scott Purviance, chief executive officer, Amwins
• David Blades, associate director, AM Best

Attendees can submit questions during registration or by emailing webinars@ambest.com . Playback of the session will be available shortly after the live event for those unable to attend.

About AM Best

AM Best is a global credit rating agency, news publisher, and data analytics provider specializing in the insurance industry. Headquartered in the United States, the company operates in over 100 countries with regional offices in London, Amsterdam, Dubai, Hong Kong, Singapore, and Mexico City.