Do You Need Exactly 100 Shares to Sell a Covered Call? What Happens If You Own Fewer

The Short Answer: Yes, One Contract Requires 100 Shares

Yes, you need exactly 100 shares to sell one standard covered call contract in the US or Canadian markets. Each equity options contract controls exactly 100 shares of the underlying stock. If you own fewer than 100 shares and sell a call, the portion not backed by stock is considered uncovered — and that changes everything about your risk profile.

This is not a brokerage quirk. It is how options contracts are structured across every major US exchange. The Options Industry Council (OIC) defines a covered call as a strategy where the seller owns the equivalent number of shares to cover the obligation. Sell one call, own 100 shares. Sell two calls, own 200 shares. The math is fixed.

Why the 100-Share Rule Exists

Options contracts are standardized. The 100-share multiplier is set by the exchanges and clearing organizations — primarily the Options Clearing Corporation (OCC) — so that every contract traded on CBOE, NYSE American, or any other US options exchange represents the same underlying quantity. This standardization is what makes options liquid and easy to price.

When you sell a covered call, you are giving the buyer the right to purchase your 100 shares at the strike price before expiration. If the stock gets called away, you deliver those 100 shares and collect the strike price. If you only own 60 shares, you can only deliver 60. The other 40 shares would have to be purchased in the open market at whatever price is trading that day — potentially much higher than your strike. That is real, uncapped loss exposure.

What Happens If You Sell a Call With Fewer Than 100 Shares?

If you own, say, 60 shares of Apple (AAPL) and sell one call contract, 60 of those shares are covered. The remaining 40-share obligation is naked — meaning you have sold a call with no stock backing it. Most retail brokers will not allow this. FINRA rules require brokers to assign appropriate options approval levels to accounts, and selling naked calls typically requires a higher approval level than covered calls because of the unlimited loss potential.

If your broker does allow it — perhaps because your account has margin and a higher options tier — you are now running a partially covered, partially naked position. The naked portion requires margin collateral. The SEC and FINRA both treat uncovered short calls as high-risk positions subject to margin requirements. If AAPL spikes sharply, the broker can issue a margin call or liquidate positions to cover the shortfall. This is not a theoretical risk. It is a real scenario that has wiped out retail accounts.

Bottom line: if you own fewer than 100 shares, do not sell a covered call on that position. You are not running a covered call strategy anymore.

A Worked Example: Selling One Covered Call on AAPL

Let's say AAPL is trading at $195 per share. You own exactly 100 shares, giving you a position worth $19,500. You decide to sell one AAPL call with a $200 strike price expiring in 30 days. The premium is $2.10 per share, so you collect $210 upfront (100 shares × $2.10).

Scenario A — Stock stays below $200 at expiration: The call expires worthless. You keep your 100 shares and the $210 premium. Your effective cost basis on the shares drops by $2.10 per share.

Scenario B — Stock rises to $207 at expiration: The buyer exercises the call. You sell your 100 shares at $200 (the strike), collecting $20,000 plus the $210 premium you already received — a total of $20,210. You miss the gain above $200, but you still made money. Your shares are gone, and you need to decide whether to buy back in.

Now imagine you only owned 60 shares and still sold that one contract. In Scenario B, you deliver your 60 shares at $200 but still owe 40 shares to the buyer. You must buy those 40 shares at the market price of $207, paying $8,280 for shares you immediately sell at $200 ($8,000). That is an $280 loss on the naked portion alone — more than the entire $210 premium you collected. And if AAPL had spiked to $220, the loss on those 40 shares would have been $800, nearly four times your premium. The math turns against you fast.

What Are Your Options If You Own Fewer Than 100 Shares?

You have a few practical paths forward.

Buy up to 100 shares. The most straightforward fix is to purchase enough additional shares to reach 100. If you own 75 shares of Microsoft (MSFT) at $420 and want to sell covered calls, buying 25 more shares gets you to a full contract. Yes, that requires capital, but it keeps your strategy clean and your risk defined.

Wait and accumulate. Some investors use a dividend reinvestment plan (DRIP) or regular contributions to build toward 100 shares before starting covered calls. This is a disciplined approach that avoids taking on unintended risk.

Consider ETF alternatives. If you want covered call income but cannot afford 100 shares of a high-priced stock, some investors use lower-priced ETFs or stocks where 100 shares is more accessible. SPY, for example, trades around $530 — still $53,000 for 100 shares — but there are sector ETFs and individual stocks with lower per-share prices that still have active options markets.

Look at mini options (with caution). Mini options — contracts covering just 10 shares — existed on a handful of stocks including AAPL and GOOG, but CBOE delisted most of them due to low volume. As of now, mini options are largely unavailable for retail traders on standard US exchanges. Do not count on this as a workaround.

For Canadian investors, the same 100-share standard applies on the Montreal Exchange (MX). The CRA treats covered call premiums as either capital gains or income depending on your trading frequency and intent — a distinction that matters at tax time regardless of how many contracts you sell.

The Real Risks You Should Not Skip Over

Covered calls are often marketed as low-risk income strategies, and compared to buying options outright, they are. But they carry real risks that every trader needs to understand before selling a single contract.

Assignment risk is always present. If the stock closes above your strike at expiration — or sometimes even before expiration on American-style options — the buyer can exercise and take your shares. You will receive the strike price, but you lose any upside above it. If you needed those shares for a long-term holding or tax reason, assignment can be disruptive.

Opportunity cost is a real loss. If AAPL jumps from $195 to $230 and your call was struck at $200, you capped your gain at $200. That $30-per-share difference is real money you did not make. The premium you collected does not come close to covering it.

Early assignment on dividend-paying stocks. If you sell a call on a stock that pays a dividend, the buyer may exercise early to capture the dividend. The OIC has published guidance on this. Know your ex-dividend dates before selling calls on dividend stocks.

Tax treatment is not automatic. In the US, the IRS treats covered call premiums differently depending on whether the call is qualified or non-qualified under Section 1256 and related rules. Premiums received are generally not taxed until the position closes, but the details matter. Consult a tax professional. In Canada, the CRA's position on whether premiums are income or capital gains depends on your overall trading activity — frequency, intent, and holding period all factor in.

How Brokers Enforce the 100-Share Requirement

Your broker is your first line of enforcement. When you enter a covered call order, the broker's system checks your account for the underlying shares. If you have 100 shares, the order goes through as a covered write. If you have fewer, most retail platforms — Fidelity, Schwab, TD Direct Investing, Questrade, and others — will either block the order or route it as an uncovered call requiring a higher options approval level.

FINRA Rule 4210 governs margin requirements for options positions, and brokers must comply. Selling a naked call without sufficient margin or approval is not something a standard Level 1 or Level 2 options account permits. If you are unsure what approval level your account has, check your broker's options agreement or call their trading desk.

One practical tip: before selling any covered call, confirm your share count in your account's holdings tab, not just your memory of what you bought. Corporate actions like stock splits, spin-offs, or partial sales can leave you with a non-round lot without you realizing it.

Can I sell a covered call if I only own 50 shares?

No, not as a true covered call. One standard options contract covers 100 shares, so owning only 50 shares means half of your obligation would be uncovered — essentially a naked call on that portion. Most retail brokers will block this order unless you have a high-level options approval and margin account. The risk on the uncovered portion is theoretically unlimited.

What happens if I get assigned on a covered call and I only had 100 shares?

If you are assigned, your broker automatically transfers your 100 shares to the call buyer and deposits the strike price times 100 into your account. You keep the premium you collected when you sold the call. After assignment, your position in that stock is zero, and you are free to buy shares again if you want to restart the strategy.

Do I need 100 shares per contract or 100 shares total?

You need 100 shares per contract you sell. If you want to sell two covered call contracts, you need 200 shares. Three contracts require 300 shares, and so on. Each contract is an independent obligation to deliver 100 shares if exercised.

Is there any way to sell covered calls with less than 100 shares?

Not through standard US or Canadian equity options markets. Mini options covering 10 shares were briefly available on a few stocks but were delisted due to low trading volume and are not a practical option for most retail traders today. Your best path is to accumulate shares until you reach 100 before writing calls.

How does the IRS tax the premium I collect from selling a covered call?

The IRS generally does not tax the premium at the time you receive it. Instead, the premium is included in the calculation when the position closes — either through expiration, buyback, or assignment. The tax treatment can also affect the holding period of your underlying shares, so covered calls on stock held near the long-term capital gains threshold deserve careful attention. Consult a qualified tax professional for your specific situation.

What if a stock split leaves me with a non-round lot — can I still sell covered calls?

After a stock split, the options contracts are typically adjusted by the OCC to reflect the new share count and price, so your existing contracts may still be covered. However, if you end up with a non-round lot like 150 shares after a split, you can sell one covered call backed by 100 shares — the remaining 50 shares are simply unhedged stock. Always verify your exact share count and any contract adjustments with your broker after a corporate action.