There are three well known reports in this regard; Vickers’ report in the UK proposes ring fencing the retail business from the investment banking activities. The Volker rule under the Dodd-Frank Act in the US proposes restrictions on proprietary trading with some exceptions and puts limitations on banks sponsoring Hedge funds, Venture Capital funds and Private Equity funds.
The policy implications would be different, depending on what really drives what. And identifying turning points in econometric models is a notoriously tricky business.