While the biggest exchange-traded fund shops such as BlackRock and Vanguard battle for fresh money by undercutting each other on fees, small and relatively new entrants of ETF-land are going whole hog.

Salt Financial, an ETF shop with less than two years under its belt, filed on Tuesday to launch an ETF that will actually pay investors for investing in it, at least at the start. The negative-fee ETF is finally here, making online lender Social Financial or SoFi’s zero-fee ETFs old news.

Filings...