Settlement Failure Repurchase Auction (Mandatory Buy-In)
The Formal Definition
A mandatory clearinghouse and regulatory process (enforced under SEC Rule 204 of Regulation SHO) where a broker-dealer that has a persistent Failure to Deliver (FTD) position is legally compelled to purchase shares on the open market at prevailing prices to close out the fail.
Mandatory Close-Out Deadline: Failure to Deliver (FTD) Persists past Settlement (T+1) → Broker Must Execute Open-Market Buy-In at T+3 Open
Cole Barrett's Reality Check
The Unvarnished Bottom Line"A mandatory buy-in is when the clearinghouse takes the wheel. If you short a hard-to-borrow stock and your broker fails to deliver the shares to the clearinghouse by the regulatory deadline, they don't wait for your permission. Under SEC Rule 204, the clearing desk fires a mandatory market order to buy the shares back at the opening bell. If the stock is squeezing, you buy at the absolute peak."
Interactive Simulator: Test the Math
Real-World Example: Scenario Breakdown
Examining the real numbers for: Holding a 2,000-share short position in a low-float equity experiencing persistent clearinghouse Failures to Deliver (FTDs)
| Execution Metric | Compliant Broker (Pre-Borrow Locate on File) | Unlocated Short Seller (Rule 204 Mandatory Buy-In) |
|---|---|---|
| Fee / Rate | $1.00 fee + standard borrow interest | $0.00 |
| Spread / Buffer | Secured verified institutional locate before executing short order | Broker failed to deliver shares; stock hit mandatory Rule 204 close-out deadline |
| Execution / Status | Shares delivered cleanly on T+1 settlement date; zero FTD recorded | Broker fired mandatory open-market buy-in at 9:30 AM open during a short squeeze |
| Total Cost / Result | Zero forced buy-in exposure | Suffered catastrophic forced buy-in liquidation at peak squeeze pricing |
How Brokers Weaponize This Term
Discount brokerages fail to alert retail short sellers when their positions are approaching statutory SEC Rule 204 buy-in deadlines, executing surprise morning buy-ins that lock in peak short-squeeze losses.
Broker Evaluation Matrix
Cole Approves
Interactive Brokers: Provides institutional short-sale dashboards displaying real-time borrow availability, locate pricing, and advance notifications of impending buy-in risks.
Read Audit →Cole Flags / Avoids
Zero-Fee Clearing Desks: High clearing failure rates that trigger frequent surprise mandatory buy-ins against retail short accounts.
View Trap Details →Frequently Asked Questions
What is SEC Rule 204?
A key regulation under Regulation SHO that requires broker-dealers to close out fail-to-deliver positions in equity securities by purchasing or borrowing shares by the beginning of regular trading hours on the applicable close-out date.
Can an investor refuse a mandatory buy-in notice?
No. Mandatory buy-ins are federal regulatory requirements enforced directly by clearing corporations (NSCC/DTCC) and clearing brokerages to ensure systemic settlement finality.