margin-operations

What this skill does

# Margin Operations

## Purpose
Guide the understanding and management of margin lending, margin requirements, and margin call operations in brokerage and advisory settings. Covers Regulation T initial margin, FINRA/exchange maintenance margin, portfolio margin methodology, margin call types and procedures, forced liquidation processes, securities-backed lines of credit (SBLOC), and margin risk management. Enables building or evaluating margin systems and understanding margin impact on portfolio management and client accounts.

## Layer
11 — Trading Operations (Order Lifecycle & Execution)

## Direction
both

## When to Use
- Calculating initial margin requirements and buying power for new trades
- Determining maintenance margin and house requirements for existing positions
- Evaluating portfolio margin eligibility and benefits for an account
- Generating, tracking, or resolving margin calls (fed calls, house calls, exchange calls)
- Designing or reviewing forced liquidation procedures and waterfall logic
- Structuring or evaluating securities-backed lines of credit (SBLOC or non-purpose loans)
- Stress testing margin exposure across portfolio scenarios
- Computing margin interest charges and their impact on investment returns
- Assessing concentrated position margin requirements and risk
- Understanding day-trade margin rules for pattern day traders
- Reviewing margin-related regulatory requirements (Reg T, Reg U, FINRA 4210)

## Core Concepts

### Regulation T Initial Margin
The Federal Reserve's Regulation T establishes the initial margin requirement for purchasing securities on credit. Key provisions:

- **50% initial margin requirement:** An investor must deposit at least 50% of the purchase price of marginable securities. For a $100,000 purchase, the investor must deposit $50,000 (cash or marginable securities); the broker-dealer may lend the remaining $50,000.
- **Reg T buying power:** The maximum dollar amount a client can purchase given their available equity. Buying power = SMA x 2 (for equity securities under Reg T). If a client deposits $100,000 cash in a new margin account, buying power is $200,000.
- **Special Memorandum Account (SMA):** A bookkeeping entry that tracks the client's excess Reg T equity. SMA increases when: the account has excess equity above 50%, securities are sold, dividends or cash are deposited. SMA decreases when used to purchase securities or withdraw cash. SMA is a high-water mark — it does not decrease when market values decline (unless used).
- **Reg T extension procedures:** When a client fails to meet the initial margin requirement by settlement date, the broker-dealer must request an extension from a self-regulatory organization (SRO). Extensions are typically granted for 1-5 business days. Failure to meet the call results in forced liquidation and a 90-day freeze (restricted account).
- **Exempt securities:** U.S. government bonds, municipal bonds, and certain agency securities are exempt from Reg T margin requirements — they can be purchased with lower or no initial margin.
- **Day-trade margin:** FINRA Rule 4210 provides pattern day traders (4+ day trades in 5 business days) with 4:1 intraday buying power (25% margin) but requires a minimum equity of $25,000. Overnight positions revert to standard 2:1 Reg T buying power.

### Maintenance Margin
After the initial purchase, ongoing maintenance margin requirements determine the minimum equity the account must maintain:

- **FINRA Rule 4210 minimum:** 25% equity for long positions. Account equity = market value of securities minus debit balance. If equity falls below 25% of market value, a maintenance margin call is triggered.
- **House maintenance requirements:** Most broker-dealers impose requirements above the FINRA minimum, typically 30-40% for diversified accounts. House requirements vary by firm and may change based on market conditions.
- **Concentrated position margin:** Single-stock positions exceeding a threshold (e.g., 40-60% of account value) face elevated margin requirements, often 50-75% or higher. This discourages excessive concentration in margin accounts.
- **Long margin formula:** Maintenance call triggered when equity / market value < maintenance requirement. Equivalently, a call is triggered when market value falls to: debit balance / (1 - maintenance requirement).
- **Short margin requirements:** Short positions require initial margin of 50% (Reg T) and maintenance of 30% of market value (FINRA minimum). Short account equity = credit balance - market value of short securities. A short squeeze (rising prices) increases the maintenance requirement.
- **Options margin:** Options strategies have specific margin requirements under FINRA Rule 4210 and exchange rules. Covered calls require no additional margin (shares serve as collateral). Naked short options require substantial margin — typically the greater of: (a) option premium + 20% of underlying value - out-of-the-money amount, or (b) option premium + 10% of underlying value. Spreads have defined-risk margin equal to the maximum loss.

### Portfolio Margin
A risk-based margining methodology that can significantly reduce margin requirements for hedged or diversified portfolios:

- **Methodology:** Uses the Options Clearing Corporation's Theoretical Intermarket Margin System (OCC TIMS) to compute margin based on the theoretical maximum loss of the portfolio under a range of stress scenarios, rather than applying fixed percentage requirements to each position independently.
- **Eligibility requirements:** Minimum account equity of $100,000 (FINRA Rule 4210(g)), options trading approval (typically Level 3 or 4), and the firm may impose additional requirements such as minimum net worth, trading experience, or completion of a portfolio margin agreement.
- **Stress test scenarios:** The OCC TIMS model evaluates portfolio profit and loss under standardized moves:
  - Large-cap equities: +/- 15% (with intermediate points at +/- 5%, +/- 10%)
  - Small-cap equities: +/- 10% higher stress (effectively +/- 25%)
  - Broad market indices: +/- 8% to +/- 15%
  - High-volatility securities: firm-specific add-ons
  - The largest theoretical loss across all scenarios becomes the margin requirement
- **Portfolio margin vs Reg T comparison:** A hedged equity portfolio with offsetting options positions might require 50% margin under Reg T (applied position-by-position) but only 10-20% under portfolio margin (reflecting the actual net risk). Conversely, a concentrated, unhedged portfolio may see little benefit from portfolio margin.
- **Benefits:** More efficient use of capital, margin requirements that reflect actual portfolio risk, ability to maintain larger or more complex positions, and alignment between margin and true economic risk.
- **Risks:** Lower margin requirements increase leverage, amplifying both gains and losses. A sudden correlation shift or gap move can produce losses exceeding the stress test scenarios. Portfolio margin accounts can experience rapid, severe margin calls during market dislocations.

### Margin Call Types
Multiple types of margin calls can arise, each with distinct triggers, deadlines, and resolution procedures:

- **Reg T initial call (federal call):** Triggered when a client purchases marginable securities and the account does not have sufficient equity to satisfy the 50% Reg T requirement. Must be met by settlement date (T+1 for most securities). Met by depositing cash or fully paid marginable securities. Failure to meet triggers liquidation and potential 90-day account restriction.
- **Maintenance margin call (house call):** Triggered when account equity falls below the firm's house maintenance requirement (typically 30-40%). The client is typically given T+5 business days (or less, at the firm's discretion) to deposit funds or securities, or the firm will liquidate positions. Unlike Reg T calls, there is no SRO extension mechanism for house calls — the timeline is at the f