Delta gets most of the attention because it is easy to understand. Price moves, option premium moves.
- Delta – How much the option price moves when the underlying moves.
- Theta – How much value an option loses with every passing day.
- Vega – How sensitive the option price is to changes in implied volatility.
- Gamma – How quickly Delta changes as the underlying price moves.
But a lot of damage in options trading comes from the Greeks traders notice much later.
For someone starting out, understanding the Greeks is less about memorising formulas and more about understanding why an option can lose money even when the market moves in the direction you expected.
I would actually say “None of the above.”
The reason is that I don’t see the Greeks as independent things that the option trader has to follow. The actual market variable is the option price. The Greeks are sensitivities derived from the option’s current market state, telling us how that price is expected to respond to changes in the underlying, time and implied volatility.
For example, Delta tells us how sensitive the option price is to the underlying, Gamma tells us how quickly that sensitivity changes, Theta quantifies time decay, and Vega quantifies sensitivity to implied volatility. They are useful measurements, but they don’t cause the option price to move.
So, in my view, it is perfectly fine to trade options while completely ignoring the Greeks. If we understand how the option price behaves in relation to the underlying, volatility, time, liquidity and order flow, wecan make decisions without ever looking at Delta, Gamma, Theta or Vega.
That said, the Greeks definitely have their use case. They are a very convenient analytical framework for quantifying exposure and understanding what is happening to an option position. For example, if an option is losing value despite the underlying moving in the expected direction, Greeks can help explain whether volatility contraction, time decay or changing Delta/Gamma is responsible.