Cash-secured vs margin-secured puts: what backs the promise?
When you sell a put, you promise to buy 100 shares at the strike. A cash-secured put backs that promise with cash you already have. A margin-secured put backs it with borrowing power, which means a loan if you're assigned.
The short answer
A cash-secured put sets aside the full strike × 100 in cash. If you're assigned, that cash buys the shares. Nothing is borrowed.
A margin-secured put sets aside only a Margin requirement, a deposit your broker works out. If you're assigned, the broker lends you the rest. You now own shares bought partly with borrowed money.
The option is the same. The backing decides what happens on a bad day.
Side by side
| Cash-secured put | Margin-secured put | |
|---|---|---|
| What backs it | Cash, strike × 100 | A margin deposit, set by the broker |
| Account type | Cash or margin | Margin only |
| If assigned | Your cash buys the shares | The broker lends the shortfall |
| Interest | None | You pay interest on the loan |
| As the stock falls | Nothing changes until expiry | The deposit can rise; a margin call is possible |
| Forced selling | No | Yes, if you can't meet a call |
| How many you can sell | Limited by your cash | Several times more |
| Allowed in IRA, TFSA, RRSP? | Usually, depending on the broker | No, these accounts don't allow margin |
A worked example (an illustration, not a trade idea)
Two traders each have $10,000. A made-up stock, XYZ, trades at $50. The 30-day $45 put pays $1.00.
Trader A, cash-secured: sells two puts. Sets aside $9,000. Collects $200.
Trader B, margin-secured: the broker asks for about $1,000 per put on the day of the trade. B sells four. Collects $400. B thinks: "I've still got buying power left over."
Then XYZ cuts its outlook. It falls to $35 by expiry, and both traders are assigned.
| Trader A: 2 cash-secured puts | Trader B: 4 margin-secured puts | |
|---|---|---|
| Shares bought at $45 | 200 shares, $9,000 | 400 shares, $18,000 |
| Paid with | Own cash | $10,000 cash + an $8,000 loan |
| Shares worth at $35 | $7,000 | $14,000 |
| Loss on shares | −$2,000 | −$4,000 |
| Premium kept | +$200 | +$400 |
| Net | −$1,800 | −$3,600 |
| Account value | $8,200, no debt | $14,000 shares − $8,000 loan + $400 = $6,400 |
B has lost twice as much. But that's not the worst part.
B's account now holds $14,000 of shares and owes $8,000. B's own money in it is only about $6,400. Brokers require a minimum share of your own money in a margin account. If XYZ drops further, say to $30, the shares are worth $12,000. B's own money is down to about $4,400 against a $12,000 position.
That can trigger a margin call. B must add cash or sell. If B can't, the broker sells shares for them, at the low price, and the loss is locked in.
| If XYZ then falls to $30 | Trader A | Trader B |
|---|---|---|
| Shares worth | $6,000 | $12,000 |
| Owed to broker | $0 | $8,000 + interest |
| Net vs start | −$2,800 | −$5,600, and a possible forced sale |
Trader A can still hold, sell calls, and wait. Trader B may not get the choice.
Why the deposit moves against you
The margin requirement isn't fixed. It's worked out from the stock price, the strike and how far in the money the put is. When the stock falls, the requirement rises. Brokers can also raise it at any time on a volatile stock.
So the deposit is smallest on the calm day you sell, and largest on the bad day you're losing. That's the opposite of what you'd want.
When margin-backed puts can work
Some experienced sellers use a margin account but size every put as if it were cash-secured. They keep the full strike amount in cash, unused. The margin is a buffer for timing, not room for more trades.
Used that way, the two are nearly the same. The risk comes from using the extra buying power. If you open a margin account, write your own cap: total strike × 100 across all puts must stay under your cash.
Which one belongs in the wheel?
The wheel strategy assumes you'll be assigned and hold the shares. A cash-secured put makes that easy: the shares are fully paid, and you can wait as long as you need.
A margin-secured put turns assignment into a loan. That adds interest, margin calls and the chance of a forced sale, the three things that end a wheel early.
In Canada, a TFSA or RRSP can't use margin. Cash-secured puts there depend on the broker, and options permissions differ by broker. See our cash-secured put guide for every outcome of the first step.
Questions
Is a margin-secured put the same as a naked put?
Mostly, yes. Both mean the put is backed by a margin deposit instead of the full cash. Brokers often call it a naked or uncovered put.
Do I pay interest on a margin-secured put?
Not while it's open. You pay interest only if you're assigned and the broker lends you money to buy the shares.
Can I sell margin-secured puts in an IRA?
Generally no. IRAs don't allow borrowing, so puts there must be cash-secured, if your broker allows them at all.
What happens in a margin call?
Your broker asks you to add cash or securities by a deadline. If you don't, or the drop is fast, the broker can sell your positions without asking.
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