National Securities Clearing Corporation
The National Securities Clearing Corporation (NSCC) is a subsidiary of DTCC that provides clearing, settlement risk management, and netting services for equity transactions in the United States, reducing the volume of securities and cash that must actually change hands by matching and offsetting buy and sell obligations across all participants.
The NSCC serves as the central counterparty (CCP) for virtually all equity and ETF transactions executed on US securities exchanges and many over-the-counter markets. When a trade is executed, NSCC interposes itself between the buyer's broker and the seller's broker, becoming the buyer to every seller and the seller to every buyer. This novation eliminates bilateral counterparty risk — no individual broker needs to worry whether the specific counterparty on the other side of its trade will fail to deliver; instead, each broker is only exposed to NSCC itself, which maintains substantial financial resources to guarantee settlement.
Netting is NSCC's most economically powerful function. Rather than settling each trade individually — which would require massive flows of securities and cash between hundreds of broker-dealers multiple times daily — NSCC calculates each participant's net obligation across all its trades in a given security over the trading day. If a broker bought 1,000 shares of Apple in one transaction and sold 900 shares in another, its net obligation is to receive only 100 shares and pay the net cash difference. This multilateral netting reduces settlement obligations by approximately 98%, according to DTCC data, dramatically reducing systemic risk and operational costs across the industry.
NSCC operates the Continuous Net Settlement (CNS) system, which processes equity transactions through a rolling net-settlement process. It also maintains a Clearing Fund (a pooled margin arrangement funded by participant contributions) to cover default risk if a participant fails to settle its obligations. The fund is calibrated based on historical volatility and net exposure levels.
During periods of extreme market volatility — the March 2020 COVID crash, the January 2021 meme stock episode — NSCC's risk models generate dramatically higher margin calls on broker-dealers carrying large unsettled obligations. The margin call Robinhood received from NSCC on January 28, 2021 (in excess of $1 billion at its peak, ultimately settled for a smaller amount) was the proximate cause of Robinhood's controversial decision to restrict trading in GameStop and other meme stocks that morning, triggering congressional hearings and regulatory scrutiny.
The transition from T+2 to T+1 settlement, completed in May 2024, was designed in part to reduce the credit and market risk that NSCC manages between trade execution and final settlement — a shorter window leaves less time for adverse price movements and counterparty defaults.