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, the data showed.
($1 = 0.9127 euros)
(Reporting by Marc Jones; Editing by Amanda Cooper)