The “option symbol” (or OCC option root) is a standardized code that uniquely identifies each contract. Since 2010, the OCC has required a 21-character format, making it easier for electronic systems to process and for humans to interpret.
The format is:
[Underlying][YYMMDD][C/P][Strike Price]
The ticker symbol of the underlying asset (e.g., GOOG for Alphabet). Padded to 6 characters with spaces.
The expiration date in year, month, and day format.
“C” for call, “P” for put.
An 8-digit number, with leading zeros. The strike is encoded as dollars-times-1,000: the leading 5 digits carry the whole-dollar portion of the strike and the trailing 3 digits carry the fractional cents (always thousandths). A $160 strike is 00160000, a $1,250.50 strike is 01250500, and a half-cent strike like $0.005 (yes, those exist on a few tickers) is 00000005.
Suppose you’re looking at a call option on Alphabet (GOOG) with a $160 strike price, expiring April 16, 2027. The symbol would be: “GOOG 270416C00160000”
The underlying asset (Alphabet). Note that the symbol is padded to 6 characters with spaces.
The expiration date (2027, April 16).
Call option.
$160.00 strike: dollars portion 00160, cents portion 000, i.e. , padded to 8 digits.
This format eliminates ambiguity and ensures that every option contract is uniquely identifiable. It’s especially important for institutional traders, clearinghouses, and regulatory reporting.