Folio has been doing it for over a decade (https://www.folioinvesting.com/folioinvesting/brokerage-features/dollar-based-investing-and-fractional-shares/ https:

Folio has been doing it for over a decade (https://www.folioinvesting.com/folioinvesting/brokerage-features/dollar-based-investing-and-fractional-shares/ https://www.folioinvesting.com/folioinvesting/brokerage-feat...)