The slowdown in CRE prices is expected to last for six to 12 months. : Commercial property prices appear to have stabilized, a trend likely to persist for six to 12 months, according to research firm Green Street Advisors. Property prices have cooled over the past couple of years, and Green Street’s aggregate CPPI has remained at roughly the same level as it was two years ago, said Peter Rothemund, senior analyst of strategic research at the firm, during a webinar on Wednesday about Green Street’s outlook for commercial real estate.