In the 90's my bank in the US credited my account for $115,000 I am fairly sure I didn't put in. I'd remember than, ya think?
I sat on the money... didn't notify the bank. Their mistake, let them figure it out.
Around end of the month got notice they were withdrawing $115,000. No explanation, nothing
If there is a positive, they didn't take the interest that cash earned during the month. Not much, but > 0