This is exactly what Etoro does. Etoro has many problems though. To name a few: - Many traders will keep losing trades open indefinitely and only close their w

This is exactly what Etoro does. Etoro has many problems though. To name a few: - Many traders will keep losing trades open indefinitely and only close their winning trades. This way they get a 100% success rate because all their realized trades were profitable. This also leads to huge realized profit percentages while the total value of their portfolio was just decreasing because of the losing trades. - You start copying them later, so you won't get all their trades. This means that your available balance percentage will be different than theirs, resulting in strange behavior when they up their stop loss with additional funds, whereas you don't have any additional funds left. This also happens when they of you withdraw/deposit funds.