🇪🇺 ECB's "business model" is as follows:
➕ income: ECB creates money and invests it into financial assets (e.g.: FX, bonds, funds)
➖expenses, such as operational expanses (e.g. staff), facility and open market operation expenses (e.g. TARGET)
profit/loss = income - expenses
equity is the residual claim on assets after all liabilities are paid
equity = assets - liabilities
so the ECB just covers the loss with their equity. this equity reduction is carried forward to be offset by future profits