The Global X Health & Wellness ETF looks sick.

Launched on May 10 as a play on “healthy alternatives,” the fund has seen an average of 259 shares change hands per day. On half of those, no shares sold at all. While that’s thin volume, it would be the envy of iShares’ MSCI International Developed Size Factor ETF, which in 14 months has had 2,725 shares trade. Total.

Around U.S. markets, uptake for new ETFs is slowing down. Securities launched in the last year have had a tougher time finding a fan base, posting around 3,300 shares of average daily volume after three months, less than half the level of two years ago. The median fund has a market value of $5.1 million 90 days after its debut, compared with $10.1 million in 2014.

Could there be a limit on how many ETFs the world needs? It’s an impolite question in money management circles, where assets in the industry have swollen 10-fold in a decade and somebody comes up with a new one to lure investor cash literally every day. At the same time, it isn’t an outlandish concern in a market stuffed with 16 securities tracking consumer staple makers and 37 tied to banks, most of which trade very little.

Peak ETF

“The ETF industry has a relatively low barrier to entry, but a very high barrier to success,” said Dan Draper, head of Invesco PowerShares. “It’s becoming increasingly difficult for new companies’ products to get liquidity and distribution, and also gain the confidence of investors. You have a lot of new issuers and offerings, but that ironically makes it more difficult for new entrants to gain traction.”

Whether we will one day reach peak ETF is of particular interest to American exchanges, which make money from frenetic trading in the stock-like products. While there’s no sign issuers are slowing down or investor ardor for the concept is weakening, equity markets lately have found themselves fighting to list funds that are almost as likely to lumber into dormancy as catch on.

Consider regional banks, where the two largest ETFs are also the oldest: the $1.7 billion SPDR S&P Regional Banking ETF and the $285 million iShares U.S. Regional Banks ETF. Since they were launched in mid-2006, five additional regional banking funds have been started, none of which comes close to their predecessors in market capitalization or trading volume. Four funds started between 2010 and 2015 never exceeded $41 million in assets.

‘Getting Heated’

Lengthening odds of success have done nothing to discourage sponsors from launching new ones. Nor has it kept exchanges from fighting for listings, mainly because ETFs, the retail stock market’s most successful innovation in a decade, account for 30 percent of trading on American exchanges. About half of ETFs are profitable, according to Bloomberg Intelligence analyst Eric Balchunas.

Bats Global Markets Inc. expects ETF assets under management to reach more than $15 trillion in 10 years and is staking its future partly on an ability to grow with the industry. More than 270 U.S.-listed ETFs were launched in 2015, almost double the number started just two years prior. This year, 141 new funds have already been originated.