In an earnings call last week, Walmart announced that its workers weresigning up for health insurance en masse. The news was bad for the company’s shareholders, since the added $500 million it will cost to cover them will eat into expected profits. But it also means that many more low-income families have health insurance now than did last year.

Health Insurance

The change didn’t come because of a more generous company policy. Walmart has long offered health insurance to its full-time workers for relatively low premiums — about $18 every two weeks for its lowest-paid workers. It came because many more workers decided to take advantage of the offer.

It’s early yet to be sure of a strong trend, but the Walmart experience mirrors evidence from early polls and the historical experience of Massachusetts, which enacted a law similar to the Affordable Care Act in 2006. More people may be signing up for employer-based coverage than did before.

When we talk about the effect of the Affordable Care Act on health insurance, we often focus on people who were shut out of the market before, either because a prior illness made insurance inaccessible to them or because a high premium put coverage out of their financial reach. What Walmart’s experience reminds us is that there were also uninsured people who simply chose not to buy coverage before there was a law requiring them to do so. Now they may be changing their minds.