Here in the US I'd know to never keep over 100k in a bank account, I think FDIC has been raised to 200k now since the financial crisis. But why... oh why would you keep such a large amount in a single account? The insurance is simply the cost of opening a few new free accounts.
I'm guessing that this account fluctuated from very high to very low, over the course of a month, and it just had the misfortune of being caught at a high point.