securities. Key quantitative inputs for these models are daily observed benchmark curves for treasury, swap and high quality credits. The pricing services then apply a credit spread to the respective curve for each security which is developed by in-depth and real time market analysis. For securities in which trade volume is low, the pricing services utilize data from more frequently traded securities with similar attributes. These models may also be supplemented by daily market and credit research for international markets. Corporate Level 2 - At December 31, 2021, the Company’s corporate fixed maturity investments principally consisted of U.S. and international corporations and had a weighted average yield to maturity of 2.8% and a weighted average credit quality of BBB ( 2020 - 2.2% and BBB, respectively). The Company’s corporate fixed maturity investments are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources regarding the issuer of the security and obtain credit data, as well as other observations, from markets and sector news. Evaluations are updated by obtaining broker-dealer quotes and other market information including actual trade volumes, when available. The pricing services also consider the specific terms and conditions of the securities, including any specific features which may influence risk. In certain instances, securities are individually evaluated using a spread which is added to the U.S. treasury curve or a security specific swap curve as appropriate. Agency Mortgage-backed Level 2 - At December 31, 2021, the Company’s agency mortgage-backed fixed maturity investments included agency residential mortgage-backed securities with a weighted average yield to maturity of 1.9%, a weighted average credit quality of AA and a weighted average life of 5.6 years ( 2020 - 1.0%, AA and 3.8 years, respectively). The Company’s agency mortgage-backed fixed maturity investments are primarily priced by pricing services using a mortgage pool specific model which utilizes daily inputs from the active to-be-announced market which is very liquid, as well as the U.S. treasury market. The model also utilizes additional information, such as the weighted average maturity, weighted average coupon and other available pool level data which is provided by the sponsoring agency. Valuations are also corroborated with active market quotes. Non-agency Mortgage-backed Level 2 - At December 31, 2021, the Company’s non-agency mortgage-backed fixed maturity investments had a weighted average yield to maturity of 3.2%, a weighted average credit quality of non-investment grade and a weighted average life of 5.7 years ( December 31, 2020 - 3.0%, non-investment grade and 5.2 years, respectively). Securities held in these sectors are primarily priced by pricing services using an option adjusted spread model or other relevant models, which principally utilize inputs including benchmark yields, available trade information or broker quotes, and issuer spreads. The pricing services also review collateral prepayment speeds, loss severity and delinquencies among other collateral performance indicators for the securities valuation, when applicable. Commercial Mortgage-backed Level 2 - At December 31, 2021, the Company’s commercial mortgage-backed fixed maturity investments had a weighted average yield to maturity of 1.9%, a weighted average credit quality of AA, and a weighted average life of 4.1 years ( 2020 - 1.5%, AAA and 5.0 years, respectively). Securities held in these sectors are primarily priced by pricing services. The pricing services apply dealer quotes and other available trade information such as bids and offers, prepayment speeds which may be adjusted for the underlying collateral or current price data, the U.S. treasury curve and swap curve as well as cash settlement. The pricing services discount the expected cash flows for each security held in this sector using a spread adjusted benchmark yield based on the characteristics of the security. F-33