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Annualized option premium: the math, and the month that breaks it

Annualizing takes the premium from one short trade and scales it up to a year, as if you could repeat it with no losses. It's useful for comparing two trades of different lengths. It's misleading as a picture of what a year will look like, and one losing trade shows why.

Options guide · 9-minute read · Updated 2026-10-27

The short answer

To annualize a premium, divide it by the cash set aside, then scale it to 365 days. A $1.00 premium on a $45 put held 30 days is about 2.2% of the cash, which annualizes to roughly 27%.

That number assumes every trade for a year looks like this one: no assignments, no losses, no idle cash. In real selling, losing trades happen. One of them can erase most of a year's premiums. Use annualizing to compare trades, never to forecast a year.

The math, step by step

The example below is hypothetical, with round numbers (an illustration, not a trade idea). A made-up stock, XYZ, trades at $50. You sell a 30-day $45 put for $1.00. You collect $100. Your broker sets aside $4,500.

1. Return on the cash for this trade: $100 ÷ $4,500 = 2.2% for 30 days.
2. Simple annualized: 2.2% × (365 ÷ 30) ≈ 27%.
3. Compounded annualized: (1 + 0.022) raised to the power of (365 ÷ 30), minus 1 ≈ 31%.

Brokers, screeners and calculators show one of these. The Annualized premium glossary page has the one-line definition.

Why it's useful

Annualizing puts trades of different lengths on one scale.

Trade B collects more dollars, but ties up the cash twice as long. Trade C looks best of all on the annualized line. That's the first warning: short trades produce big annualized numbers, because a small premium is multiplied by 52. They also give you the least time to react. See gamma risk for option sellers.

The month that breaks it

Now the losing case, worked out. You keep selling Trade A, one at a time, for a year. Eleven expire. On one, XYZ falls hard and closes at $38 on expiry day.

• You're assigned. You buy 100 shares at $45: $4,500.
• They're worth $38: −$700 on the shares.
• You keep that trade's premium: +$100.
• That trade's result: −$600, about −13% of the cash.

If you annualized that trade the same way, you'd get roughly −160%. Nobody quotes that figure. It's as meaningless as the +27%, just in the other direction.

A year of trades, three ways

Here's the same 12 trades with different numbers of bad ones. Assume, to keep it simple, that you sell the assigned shares at expiry and start again.

The "premiums kept" column is the same in every row. That's the point: the premium is the part you can count on. The losses are the part that decides the year.

What else annualizing leaves out

• Idle cash. Between trades, the cash may sit unused for days. Annualizing assumes it's always working.
• Assigned shares. After assignment in the wheel strategy, you hold the shares and sell calls. Those calls are often smaller, especially on a stock that fell. The cash is tied up in a losing position, not earning the put's rate.
• Fees and spreads. Each trade pays commissions and gives up part of the bid-ask spread. Short trades pay that more often.
• Taxes. Short-term gains on options are often taxed at a higher rate than long-term gains on shares. General information, not tax advice; check with a tax professional or your broker.
• Changing premiums. The 2.2% depended on today's Implied volatility. When the market calms, the same strike pays less.

How to use it honestly

1. Use it only to compare. "Is a 30-day or a 45-day put a better use of this cash?" is a fair question for annualizing.
2. Never add up annualized figures into a plan. A year is not twelve copies of one good trade.
3. Look at the dollar loss first. Before any yield number, write down what the trade loses if the stock falls 20% and 30%. That's your real exposure.
4. Track your actual year. In your journal, add up every premium and every loss. That number is the only annualized figure that counts.

Premium as a percent of cash set aside is the plainer yardstick most sellers start with. Compounding premium, the honest version shows what happens when losses are left in.

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