Hi Denimac,
This is a good question. This is QuickBook's way of letting you know that your bank balance is in negative.
Furthermore, notice that these figures are under is "Balance" column, so every time transactions are entered, the running balance changes depending on the type of transaction if it's a money in or a money out entry. The figure in this column turns red if it is a negative running balance. For example, your current balance is $1000 then an expense for $1500 is entered, that balance column will be a negative $500 and it will be in red.
Let us know if you have further queries and we'll be happy to help! Cheers!
