Firth Ratings has issued a warning - a general one, not about any specific fund or provider of them - concerning open-ended bond funds. The essential and basic idea of such funds leaves them potentially vulnerable to the same problems banking is. That of a bank run where withdrawals outpace the ability to collect on assets. We have, in fact, seen these in slightly different funds, open-ended property investment ones. The concern is real.
Here's Fitch:
Open-ended bond funds are a potential risk to global financial stability given their rapid growth and increasing liquidity