What does a positive delta mean?

A positive delta means that two variables move in the same direction or that there has been an increase. In general mathematics and science, a positive delta means final value is greater than initial value. If ΔT is positive, temperature went up. If Δx is positive, position moved forward. It indicates growth, increase, or forward change. In finance and options trading, a positive delta has a very specific meaning. For stock options, a positive delta between 0 and 1 means you have a bullish position that benefits when the underlying stock price goes up. Call options always have positive delta from 0 to 1. For example, a call with a delta of 0.70 means if the stock goes up $1, the call option should increase by about $0.70. Shares of stock themselves have a delta of 1.0 or 100, meaning they move dollar for dollar with themselves. So a portfolio with a net positive delta will profit if the market rises. In chemistry, a positive delta can mean a partial positive charge, written as δ+, indicating an atom that has lost some electron density, like the hydrogen atoms in water. In business performance, a positive delta means you exceeded target. So overall, positive delta means increase, bullish, or same-direction movement, while negative delta means decrease or inverse movement.