Option Symbology on US Exchanges
Option Symbology on US Exchanges
US-listed equity options use a standardized ticker format established by the Options Clearing Corporation (OCC). Understanding this symbology helps you identify exactly which contract you're trading and avoid costly order errors.
Definition and Key Concepts
The OCC Option Symbol Format
The standard option symbol contains 21 characters organized into four components:
[Root Symbol][Expiration Date][Option Type][Strike Price]
| Component | Length | Description |
|---|---|---|
| Root Symbol | Up to 6 characters | Underlying stock or ETF ticker |
| Expiration Date | 6 characters | YYMMDD format |
| Option Type | 1 character | C = Call, P = Put |
| Strike Price | 8 characters | Price in dollars (5 digits) + cents (3 digits) |
Example Breakdown
Consider the symbol: AAPL250117C00175000
| Component | Value | Meaning |
|---|---|---|
| Root | AAPL | Apple Inc. stock |
| Expiration | 250117 | January 17, 2025 |
| Type | C | Call option |
| Strike | 00175000 | $175.00 strike price |
This represents an Apple $175 call expiring January 17, 2025.
Strike Price Encoding
The strike price uses 8 characters:
- First 5 digits: Dollar amount (right-justified, zero-padded)
- Last 3 digits: Decimal portion (cents/fractional dollars)
| Strike Display | Encoded Format |
|---|---|
| $50.00 | 00050000 |
| $175.00 | 00175000 |
| $7.50 | 00007500 |
| $1,250.00 | 01250000 |
| $42.50 | 00042500 |
How It Works in Practice
Reading Symbols in Your Platform
Most trading platforms display simplified versions but use full OCC symbols for order routing. You might see:
Platform Display: MSFT Jan 17 '25 $400 Call Full Symbol: MSFT250117C00400000
When placing orders, verify the full symbol matches your intended contract—especially when strikes are close together or multiple expirations exist.
Special Cases
Adjusted Options: Corporate actions (splits, special dividends, mergers) can create adjusted options with non-standard terms. These often have modified root symbols:
- AAPL1 instead of AAPL for adjusted contracts
- The deliverable may differ (e.g., 50 shares instead of 100)
Mini Options: Some stocks offer mini options controlling 10 shares instead of 100. These use a modified root symbol, though availability is limited.
Weekly Options: Weekly expirations use the same symbology—the expiration date component distinguishes them from standard monthly options.
Symbol Lookup and Verification
Before trading, confirm:
- The underlying matches your intent
- The expiration date is correct (month, day, year)
- The option type (C or P) matches your directional view
- The strike price is accurate, including decimal points
Worked Example
Task: Decode and verify an option symbol
You want to buy a Tesla put with a $200 strike expiring March 21, 2025.
Step 1: Construct the expected symbol
- Root: TSLA
- Expiration: 250321 (2025, March, 21)
- Type: P (put)
- Strike: $200.00 = 00200000
Expected Symbol: TSLA250321P00200000
Step 2: Verify in your platform
Your platform shows: TSLA Mar 21 '25 $200 Put Full symbol displayed: TSLA250321P00200000
Match confirmed. The contract is correct.
Common Error Example:
You intend to buy the $195 put but accidentally select the $200 put:
- Intended: TSLA250321P00195000
- Selected: TSLA250321P00200000
A $5 strike difference significantly affects delta, premium, and probability of profit. Always double-check strike encoding.
| Symbol Component | Correct | Error |
|---|---|---|
| Root | TSLA | TSLA |
| Expiration | 250321 | 250321 |
| Type | P | P |
| Strike | 00195000 | 00200000 |
Risks, Limitations, and Tradeoffs
Adjusted Option Confusion
Adjusted options may have identical-looking strikes but different deliverables. For example, after a 2-for-1 split:
- Standard new option: 100 shares at $50 strike
- Adjusted pre-split option: 200 shares at $50 strike
The adjusted contract uses a modified root symbol. Trading the wrong series produces unexpected results.
Date Format Errors
The YYMMDD format can cause confusion:
- 250321 = March 21, 2025
- 250117 = January 17, 2025
Mixing up month and day leads to wrong expirations—particularly problematic near monthly option expiration dates.
Strike Decimal Placement
Incorrectly interpreting the 8-digit strike creates significant errors:
- 00042500 = $42.50
- 00425000 = $425.00
One misplaced mental decimal turns a reasonable trade into an impossible one.
Platform Variations
While the OCC standard is universal, platforms may display symbols differently:
- Some use spaces between components
- Some abbreviate or truncate
- Some show only simplified versions in the interface
Understand how your specific platform displays and routes option orders.
Common Pitfalls
-
Ignoring the year digit: Options expiring in different years can have similar symbols. Verify the full date.
-
Missing adjusted option flags: The "1" or other suffix after the root indicates a non-standard contract.
-
Assuming standard deliverable: Always confirm the contract represents 100 shares of the expected underlying.
-
Fat-finger errors on strike: Entering $425 instead of $42.50 (or vice versa) is easy when typing quickly.
-
Confusing C and P: A single-letter error reverses your directional exposure entirely.
Checklist for Symbol Verification
- Confirm the root symbol matches the underlying you intend to trade
- Verify the expiration date (year, month, day)
- Check that C or P matches your call or put intention
- Decode the strike price including decimal placement
- Look for adjusted option indicators (modified root symbols)
- Cross-reference the full symbol with your trading platform display
- Review order confirmation before submitting
Next Steps
With symbology understood, you can navigate the clearing process that ensures trades settle properly. Learn about the OCC's role in Clearing and OCC Guarantees.
For background on interpreting the option chain where these symbols appear, see Open Interest and Volume Signals.