Advisors say single-stock ETFs are more appropriate for short-term institutional traders who understand the inherent risks, not for retail clients.

"Complex" ETFs are a fast-growing corner of the $6.4 trillion industry.

The RiverNorth Enhanced Pre-Merger SPAC ETF (SPCZ) launched last week, investing in so-called special purpose acquisition companies before they merge with their targets.

ETF fund issuers saw filings drop in half after Russia's invasion of Ukraine roiled markets, essentially finishing the first half flat.

At least 85 more single-equity ETFs are planned by 37 companies.

Franklin Templeton aims to quadruple its ETF business in the next three years.

The fund will seek to invest in U.S.-listed companies with a “track record of creating American jobs.”