For the sixth consecutive quarter, private commercial mortgages held by life insurance companies delivered a positive price performance, according to a report from Boston-based LifeComps.

Third quarter 2010 delivered a 4.01 percent total, contributing to a 12-month total return of 16.03 percent, according to the report. Third quarter’s gain followed total returns of 4.64 percent in the second quarter, 4.25 percent in first quarter and 2.25 percent in fourth quarter 2009.

Of the four major property types, apartments performed best over 12 months with a total return of 18.4 percent compared to 17.64 percent for retail, 14.73 percent for office and 14.01 percent for industrial.