Let me provide some information about opening balance, @Charries.
A Negative equity in Credit Card account can be caused by an incorrect opening balance or transactions that are older than the opening balance. When you create a new account in QuickBooks, you pick a day to start tracking transactions. Then, you enter the balance of your real-life bank account for whatever day you choose. This amount and the start date set the account's opening balance.
To fix this, let's start by reviewing and updating the opening balance entry in the Chart of Accounts.
Open your company file.
Go to the List menu and then select Chart of Accounts.
Choose the Credit card account and then right-click.
Select Edit account.
Click the Change the Opening Balance button and then edit the amount.
@Charries I believe what you are talking about is the negative balance in your Equity account (most likely Opening Balance Equity with a new file) that offsets the positive credit card balance. A balance sheet must always "balance". The top half (Assets) is everything your business "owns". The bottom half (Liabilities and Equity) is everything your business "owes". Equity is the owners' "value" in the business - the difference between what you own and what you owe. When you enter a credit card balance, you owe the money, so it will reduce the owners' value, therefore creating negative equity. Does that help?