Think of this. When there was a fail to deliver by the delivering broker, the NSCC-DTC stepped in and through their Stock Borrow Program (begun in 1981) simply delivered shares to the receiving broker. Where did NSCC get those shares from? Did they borrow them from some one else's  account? Did they deliver mere notational (or fictional) shares to keep the naked short going and thereby relieve the naked shorter from being forced to cover then and there? It's no wonder the DTC was plagued by law suits against this practice.

"The NSCC Stock Borrow program was created in 1981 with the approval of the SEC to help reduce potential problems caused by fails, by enabling NSCC to make deliveries of shares to brokers who bought them when there is a 'fail to deliver' by the delivering broker. "