Prior reports have indicated that average premium increases across the country were substantial in 2016. This masks considerable variation both across and within states. We have analyzed the lowest cost silver plan premium available in each rating region across the country to identify the market characteristics most associated with premium increases and decreases. These include but are not limited to the number of participating insurers, the level of 2015 premiums, and the types of insurers participating within the markets. We conclude that there is no meaningful national average- the significant variation from state to state reflects varying levels of competition around the country.