Where does this fail in the Swiss markets? A benchmarking conducted on only 250 S&P 500 stocks is not sufficient evidence to claim large-scale portfolio optimization.
The weak link here is that this test ignores overall diversification and the asset complexity typically found in Swiss mandates, for example.
Our portfolios include much more than U.S. stocks: we manage thousands of instruments, from trust bonds to commodities, including exotic currencies and derivative products across numerous jurisdictions.
Confirming the robustness of such a system would require, at a minimum, a simulation including liquidity risks specific to each market and local regulatory constraints.
For a Swiss private bank, a portfolio of 250 stocks is anecdotal, whereas operational reality demands dynamic optimization across tens of thousands of global positions.