Option Greeks measure how an option's price responds to changes in the stock price (delta and gamma), time (theta), implied volatility (vega), and interest rates (rho).

Gamma, theta, and vega are largest for strikes near the Arthur J. Gallagher stock price and shrink for strikes far above or below it. Theta grows as expiration gets closer, while vega is larger for expirations further out. Call delta runs from 0 to 1 and put delta from -1 to 0, near 0.50 and -0.50 at the money, and roughly estimates the chance that an option finishes in the money.

Arthur J. Gallagher IV rank is 6, so implied volatility is near the bottom of its one-year range. Higher implied volatility raises option premiums and daily time decay (theta), and spreads delta and gamma across a wider range of strikes. Over the past year, 30-day implied volatility ranged from 22.1% to 173.9%. See the AJG implied volatility history for a longer view.

Across all open Arthur J. Gallagher options on Nov 4, 2026, net gamma exposure was $4.72M and net delta exposure was $167.13M per 1% move in the stock. The AJG gamma exposure chart shows where that gamma sits by strike.

Founded in 1927 as a one-person agency, Gallagher's primary business is insurance brokerage, with a focus on serving middle-market companies.