Fitch Ratings Inc. has affirmed the insurer financial strength rating of Athene Annuity & Life Assurance Co., "BBB+" with a stable rating outlook, MarketWatch reported. The West Des Moines-based company's operating earnings have been "strong since inception," Fitch Ratings said. The rating agency's rationale for the rating "reflects the company's strong earnings, solid risk-adjusted capitalization, minimal financial leverage, and market leadership position in the fixed-index annuity market. Offsetting these positives are the company's very rapid growth, relatively short operating history and somewhat aggressive investment portfolio." As a result of Athene Holdings Ltd.'s October 2013 acquisition of Aviva USA, Athene is now one of the largest issuers of fixed indexed annuities in the United States.