James River Group Holdings Ltd.’s financial strength rating was downgraded to A- from A by A.M. Best Co. Inc. on Friday, two days after the Bermuda-based insurer reported a more than $100 million quarterly loss.

In a statement, Oldwick, New Jersey-based Best said the downgrade reflected a lower assessment of the insurer’s enterprise risk management, and its rating outlook was negative due to concerns over commercial auto liability exposures.

“The risk management capabilities of the organization proved to have weaknesses in risk tolerances, non-modeled risks, management controls and risk culture. The current ERM framework and risk evaluation needs to evolve proactively and demonstrate competencies necessary to mitigate any effect on the organization’s balance sheet strength, operating performance or business profile,” the rating agency said.

Best said also it was concerned about the insurer’s balance sheet strength assessment given the recurring nature of adverse loss developments in commercial auto lines.

Noting that James River was able to replenish capital quickly via a stock offering, which it announced earlier this week, “long-term mitigation of the impact of adverse reserve development is necessary,” Best said.

On Wednesday, James River reported a $103.5 million loss for the first quarter compared with a $36.8 million loss for the same period last year.

In an earnings statement, CEO Frank D’Orazio said: “During the quarter, we continued to experience higher than expected reported losses in our large commercial auto account in runoff. In response, we meaningfully changed our actuarial methodology, resulting in a material strengthening of reserves. We believe this overhang has been eliminated.”

Commercial auto losses have been a concern for James River for several years. In the third quarter of 2019, the insurer reported a loss due to a $50 million charge related to its then-largest account, Uber Technologies Inc., which was dropped midway through the quarter.

James River did not immediately respond to a request for comment.