According to Robert Wood Johnson Foundation data that looks at state markets where all insurers must sell plans that meet Obamacare standards, regardless of how they’re purchased, more than half of the 22 million people who buy their own insurance use Obamacare marketplaces, where most of them get a federal tax credit to help pay for coverage. The rest buy directly from an insurer or broker, and they do not get a tax credit. Supporters of the Affordable Care Act hoped the law would spur more competition among insurers across the country. But so far, the law has not delivered on that promise, especially in states that never had much competition. Even before Obamacare, there have always been two distinct markets: states that still have plenty of competition and states that rely heavily on one or two insurers. In 15 states, eight or more insurers offer Obamacare plans. They are mostly the same ones where no single insurer had a dominant share of the market in 2013, before the law was enacted. But the 19 states that currently have fewer than five carriers statewide are all ones where a single insurer had more than half of the overall market before Obamacare.

. . .