For all the changes in health care over the past 10 years, the principal challenges facing medical professional liability (MPL) insurance have mostly remained the same since its crisis in the mid-2000s: a high level of capital with poor investment returns and shrinking premium.

The roughly $30 billion in capital held by the MPL industry serves as a “cushion” against systemic losses, but it also acts as a “barrier” against a hardening of the market needed to sustain underwriting discipline, said Jerry Theodorou, vice president of insurance research and asset management firm Conning.