The smaller number of public companies is an issue that could “grow in importance in the coming years,” says a recent Barron’s article.

According to private equity firm Pantheon, it reports, the number of publicly listed companies has fallen from over ten thousand to just under 6,000 last year (a 45% decline), and the firm characterizes the decline as a “disappearing act that many of us have missed.” According to Barron’s, this is attributable in large part to the fact that venture-capital and private equity firms are giving companies greater access to capital than ever before, making staying private an easy option. What’s left in the market, says Pantheon are not exhibiting the rapid growth experienced by publicly traded stocks from years gone by.

But the decline in the universe of stocks has occurred, says the article, as demand for shares has grown. “What all this means for individual investors,” it says, “has yet to be fully determined. Some have argued that the shrinking supply of public companies, coupled with greater demand for stocks because of mutual funds and ETFs, further limits the opportunity for alpha in the public marketplace.”

Thomas Clarke of macro fund manager William Blair says that the drop in publicly traded companies “is a trend that can’t run forever” and that liquidity concerns and regulation will “limit the extent to which privately held securities will be embraced by investment markets and investors alike.” The article concludes, however, that the current landscape will endure for a “long time to come.”