i am ashkenazi jew and have researched this in the past. from what i can tell, there isn't evidence the number of jews who clipped coins was higher per capita than christians who clipped coins. however, jews had much more money on average in general (as in every era and probably until the end of time), so the average jew who did clip coins was able to make more from the coin clipping than others. this led to a perception of coin clipping being a peculiarly jewish thing even though it really wasn't at all
this statistic actually basically explains most antisemitic beliefs (like stuff about finance/wall street/blackrock, representation in activist organizations and among writers and journalists, communist party leadership, etc.). even if jews are not disproportionately responsible for a certain thing, the fact that the base rate of jews in any sort of position of success across any domain is so high means any jew who does a thing will have a greater impact, be it a good thing or a bad thing
