You order a fund at 12:55. The cut-off is 13:00. Which day's price do you get?
In a case the French regulator's ombudsman looked at: the next day's. The bank's own cut-off was earlier.
A classic fund is priced once a day, after the cut-off, at a price you do not know when you order.
A share or an ETF trades on the exchange at the price you see.
Market makers keep an ETF's price close to the value of the shares inside.
Do you know your bank's cut-off time?
Education, not investment advice.
