Twelve of the top-25 insurance groups reported adverse reserve development for accident-years 2010 and 2011 during calendar-year 2012, according to new research conducted by Assured Research LLC.

In a brief research note released Thursday, William Wilt, president of the research and advisory firm, said his analysis related to development across all lines of insurance taken together. In addition, Wilt said that when analyzing development for some key commercial lines individually, anywhere from 11 to 14 of the top-25 showed adverse development for 2011, referring to the workers’ compensation, commercial multiple peril, commercial automobile and general liability lines specifically.

The analysis of 2012 Schedule P data suggests some balance-sheet driven price hikes ahead, according to Wilt.

“Throughout 2012 the industry’s rationale for raising prices conveyed a sense of management discipline”—or that an income-statement driven hardening, occurring at a “measured pace” was attributable to low interest rates, low levels of operating leverage, and improving predictive analytics.

“Tear up the script,” Wilt said, delivering the message that changes may be occurring on the liability side of insurers’ balance sheets. Although Assured’s preliminary analysis does not reveal the magnitude of the adverse development, how those amounts might measure up against takedowns for accident years prior to 2009, or if reserve releases will continue for accident-years 2008 and prior in 2013, Wilt does note that the adverse development for accident-years 2010 and 2011 is occurring in a benign loss cost environment.

“What if inflationary pressures accelerate in areas including medical and auto bodily-injury costs,” he asks.

Wilt, who also analyzes reserve trends for the 17 insurers writing predominately commercial lines insurance in the research note, promises to explore the trends further in an expanded research note later this month, available to Assured Research subscribers.