Evidence is hard: a double blind randomized control trial would be unrealistic and at a high level there would be innumerable confounders.

However, the mechanism seems simple:

1. Regulation is designed to combat inequality

2. Lower inequality is achieved thanks to this regulation

3. As inequality is lower, fewer people have spare capital for risky investments

Meanwhile, if this mechanism doesn’t work as above, that might imply we don’t (yet) have an effective way to regulate inequality down.