For a true cash secured put, the margin requirement is 100% of the strike price times 100 shares — meaning you need the full cash to buy the stock if assigned. In a margin account, brokers typically require only 20-30% of the notional value plus the put premium received. This difference significantly impacts how many contracts you can sell and your capital efficiency.

Cash Account vs Margin Account Requirements

Cash Account (Reg-T Cash Secured):

  • Requirement: Strike Price × 100
  • Example: Sell $150 put → $15,000 held as collateral
  • No leverage, no margin calls
  • Required for IRAs

    • Margin Account (Reg-T Margin):

  • Requirement: Greater of (20% of stock value − OTM amount + premium) or (10% of strike × 100 + premium)
  • Example: Stock at $165, sell $150 put for $3.20
  • Calculation: 20% × $16,500 − $1,500 + $320 = $2,120
  • That's $2,120 vs $15,000 — a massive difference

    • Portfolio Margin:

  • Requirement: Based on theoretical risk analysis (TIMS model)
  • Typically 10-15% of notional
  • Example: Same trade might require only $1,500-$2,000
  • Available for accounts over $100,000 at most brokers

    • Requirements by Broker

    | Broker | Cash Account | Reg-T Margin | Portfolio Margin | Min Account | SchwabStrike × 10020% formulaAvailable ($100K+)$0 FidelityStrike × 10020% formulaAvailable ($100K+)$0 Interactive BrokersStrike × 10020% formulaAvailable ($100K+)$0 TastytradeStrike × 10020% formulaAvailable ($125K+)$0 RobinhoodStrike × 100Limited marginNot available$0 WebullStrike × 10020% formulaNot available$0 | E*TRADE | Strike × 100 | 20% formula | Available ($100K+) | $0 |

    Broker-Specific Details

    Charles Schwab

    Schwab uses standard Reg-T margin calculations. Options approval Level 1 covers cash secured puts. Margin enhancement is automatic for margin-enabled accounts. Their platform shows buying power reduction in real time before you place the trade.

    Fidelity

    Similar to Schwab. Level 1 options in cash account, Level 2 for margin puts. Fidelity's Active Trader Pro shows margin requirements alongside the order ticket. They're conservative with margin — expect the higher end of requirement calculations.

    Interactive Brokers

    IBKR offers the most capital-efficient margin for put sellers. Their real-time margin system uses TIMS (Theoretical Intermarket Margining System) for portfolio margin accounts, often resulting in requirements 40-60% lower than Reg-T. Minimum $100,000 for portfolio margin.

    Tastytrade

    Built by options traders for options traders. Margin calculations are transparent and displayed before order entry. They've streamlined options approval — most applicants get Level 3 access quickly. Portfolio margin threshold is $125,000.

    Cash Secured vs Margin: Pros and Cons

    Cash Secured (full collateral):

  • Pro: Zero chance of margin call
  • Pro: Forced discipline — can't overleverage
  • Pro: Required for IRAs
  • Con: Ties up large amounts of capital
  • Con: Limits number of positions

    • Margin Puts:

  • Pro: Capital efficient — sell 3-5x more contracts
  • Pro: Higher percentage returns on capital
  • Con: Margin calls if positions move against you
  • Con: Can lead to overleveraging
  • Con: Not available in retirement accounts

    • The Overleveraging Trap

    With margin, you can sell a $150 put for ~$2,100 instead of $15,000. The temptation: sell seven puts and collect seven times the premium. Then the stock drops 15%, margin requirements spike, and your broker forces liquidation at the worst time.

    Rule of thumb: Even with margin, don't sell more puts than you could cover with actual cash. Use freed-up capital for diversification, not leverage on the same stock.

    OptionsPilot displays cash required per contract alongside premium yield, helping you compare capital efficiency across different stocks and strikes regardless of your broker's margin treatment.