“It’s too bad such a small percentage of the population has any real or meaningful ownership stake in equities, given their historic and current growth,” Mr. Boshara said.

Most households had less than $5,000 in total holdings in 2016, the most recent year analyzed by Mr. Wolff. Despite the slow recovery in housing prices, the wealth of middle-class Americans is still concentrated in their homes, which remain their single most valuable asset.

For 9 out of 10 households, even a shift in value of 10 percent — enough to qualify as a “market correction” — would “at most, have a 1 or 2 percent impact on their wealth holdings,” Mr. Wolff said.

If anything, foreign multinational and other investors would feel more of a pinch, since they own 35 percent of all United States corporate stock, up from 10 percent in 1982. That share of the pie exceeds the single slice owned by taxable American shareholders, defined benefit plans, defined contribution plans, or nonprofit institutions, said Steven M. Rosenthal, a senior fellow at the nonpartisan Urban-Brookings Tax Policy Center.

Don’t confuse the Dow with the economy.

The stock market and the underlying economy are distinct. The two interact, but they do not proceed in lock step or even respond to each other in predictable ways. Certainly, market instability can undermine both consumer and business confidence and restrain spending and investment. And market bubbles, swelled by overextended borrowing, can explode, wreaking losses and stalling growth.

Still, valuations of assets and the country’s economic health — as determined by productivity, employment, investment, spending, housing values, production capacity, growth and more — are two different kettles.