Colo. Rev. Stat. § 10-3-103
No domestic insurance company shall adopt the name of any existing company transacting a similar business nor any name so similar as to be calculated to mislead the public, but any domestic mutual or mutual assessment insurance company, upon complying with the terms and conditions of this title (except article 15), and article 14 of title 24, C.R.S., may be reorganized and reincorporated as a joint stock company under the same name by which it was incorporated as a mutual or assessment company, with the omission of the word "mutual", and it is unlawful for any other company to be incorporated or transact business under or by the name under which any such mutual or mutual assessment company was operating at the time of reincorporation.
C.R.S. § 10-3-103