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Options and margin

Lesson in Course: Derivatives and options (expert, 7min )

I am starting to understand the risk associated with options. Could there be a case where I can end up losing more than I anticipated?

As we have learned, options represent the contractual right between two parties on an outcome that deals with money. Options are very much zero-sum, and there's always going to be one side that's the winner of the outcome, and the other side that's the loser. The amount that is lost by one party or gained by the counterparty will always add up to $0.

When stock prices start moving quickly and delta kicks in, there's always a concern if one side will be able to hold true to their promises. We've seen cases where large institutions like banks fail to meet their promises and it lead to the subprime mortgage financial crises of 2008 where many companies went under. How do we know that we'll be able to cash in on our in-the-money options? 


The takeaways for this lesson are:

  • Learn when margin is used in combination with options
  • Understand how to avoid margin calls

Margin calls can often be quite scary when a financial institution is demanding more money from us. It's important to know how to avoid these pitfalls when we are starting out.

Margin requirements

The clearinghouse requires margin to be posted for all options traders. Margin is used as insurance to make sure that everyone gets paid at the end of the day. There are two forms of margins that can affect options traders and to make things a bit more complicated the margin required for the writer, the original seller, of an option is much higher than for buyers. Let's step through some examples of margin.

Buying call or puts

Margin requirements for buying options are minimal.

We've learned that when we buy a put or call option, the most we stand to lose is the full premium paid for our options contracts. Since we've already paid, we are not on the hook for anything additional. The caveat is that if we used margin to pay for options premiums. In that case, we are borrowing money against our account to place risky bets on options, and this is usually a recipe for disaster. We should always avoid buying options on margin.

Margin call example
  • We have $10,000 in our margin approved trading account in stocks and ETFs
  • We end up buying 2 at-the-money call options at $5 per share for a total of $1000
  • Robinhood loans us the $1000 to purchase and we don't sell any of our shares
  • Next week, poor earnings data comes out and a market correction occurs. Underlying stock price drops by 15% and the overall market is down 3%
  • the delta move on our options mean we've lost more than $900 of the borrowed $1000
  • Robinhood starts automatically selling our stock at a loss to recoup the $900

Exercising options

Auto-exercising can trigger margin purchases.

Having in-the-money call options at expiration can be a good thing. If our account is not approved for margin, typically the brokerage will sell our options on our behalf within the last hour of the maturity date. However, if we are approved for margin, our brokerage will lend us money to auto-exercise our in-the-money options. This could work in our favor if the stock price continues to go up, but it can also wipe out our hard-earned gains if the stock drops in price.

Margin call example on exercise
  • We have $10,000 in our margin approved trading account in stocks and ETFs
  • Our in-the-money call option is expiring on Friday
  • We've paid $500 in premiums for 2x $15 strike call
  • On Friday the stock is trading at $17 per share and we auto-exercise.
  • TD Ameritrade loans us $3000 on margin to purchase 200 shares of the stock at $15 per share.
  • Next few days, poor earnings data comes out and a market correction occurs. The stock is now at $12 a share.
  • TD Ameritrade initiates a margin call on the $600 loss. If we don't deposit more money, the brokerage will auto sell our stocks at a loss.

Writing options

Writing options happens when we sell options without owning them.

New options traders have made the mistake of accidentally selling a call option when they had meant to buy. While this mistake seems small, it can trigger a big margin call. Typically, most brokerages will not allow us to write options unless we have level 2 options clearance and approval for margin. Writing a call option is one of the riskiest strategies we can do because we are essentially promising the buyer of the option the right to buy 100 shares at the strike price. If we don't own 100 shares, the brokerage account will use margin to make sure we can buy 100 shares on the market.

Margin call example on writing
  • We have $10,000 in our margin approved trading account in stocks and ETFs
  • We sell an at-the-money call option with a $15 strike and get paid $250 in premiums
  • We get notified of our margin requirements but no action is needed
  • Good earnings data come out and stock jumps to $22 per share
  • We get margin called because we owe $2,200 to buy 100 shares if the buyer decides to exercise
  • WeBull automatically sells our shares to cover the margin

We can see the example above that losses rack up very quickly due to our leveraged exposure. Options grant us leverage because one contract allows us to benefit or lose as if we owned 100 shares. Leverage greatly magnifies potential gains in exchange for magnifying the risk we take. 


Margin is a helpful tool when used properly. Not understanding the risks that options introduce to margin accounts often leads beginners into unfortunate circumstances. While financial regulators do their best to safeguard everyday investors by enforcing rules, it's ultimately up to us to be able to protect ourselves. This starts by understanding what we are buying and selling before we actually take the steps to do so. Help your family and friends learn about the risks of options and margin by inviting them to the app.

At Archimedes, our goal is to make investment literacy accessible and free for everyone.

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