The data from Morningstar covered the whole of March, when a potential collapse of Credit Suisse saw Switzerland's financial authorities orchestrate its emergency takeover by rival UBS.

The data also showed that Swisscanto, another Swiss asset manager, saw the second-largest inflow of funds after iShares in March, with an estimated 6.2 billion euros pouring in.

Overall, Europe-domiciled long-term funds experienced the first combined monthly outflow since November.

Going back over the last 12 months, the data also showed Credit Suisse's funds, which Morningstar counts as either open-ended fund and exchange-traded funds, had seen money exiting every month apart from one.