Obamacare premiums for 2019 are likely to go up 5 to 10 percent nationally on top of rate increases that were previously expected as a result of the Trump administration’s suspension of health insurer transfer payments to cover sick enrollees, the head of the state insurance regulators association told Bloomberg Law.

Regardless of the outcome of a federal court case that led to a ruling against the way the Affordable Care Act risk adjustment program has been implemented, “Rates will...