Chicago Public Schools is basically relying on a credit card until property tax revenue comes in August, according to district officials.

The city’s school system made a $657 million payment into the Chicago Teachers’ Pension Fund, which is required by law. The total payment needed this year was $676 million, but CPS spokeswoman Emily Bittner says some of the payment was made earlier.

These payments have ballooned after years of not paying enough into the retirement system for city teachers. Bittner says this year’s payment is equal to 7,000 teachers’ salaries and benefits.

The district will release an estimated cash-on-hand number later today.