...Blue Cross Blue Shield of North Dakota's (BCBSND) leading market position is a key rating strength. The rating on BCBSND is attributed to the company's no. 1 market share of about 55%-60% in the North Dakota health insurance market. BCBSND's expansion into Medicare Advantage (MA), through a joint venture, and Medicaid, through a 2022 contract award with the state, will improve its business diversity and long-term competitive position. Offsetting these strengths, the rating is constrained by BCBSND's commercial membership concentration (about 80% of medical membership), single-state concentration in a relatively small market, and membership losses owing to competitive and economic pressures in recent years. BCBSND's relatively modest run-rate adjusted EBIT margin of 1%-2% is also a rating constraint. Operating performance improved in 2020-2021, following strategic investment costs that dampened 2018-2019 results. In 2021, BCBSND's statutory revenue (including investment income) was relatively...