Does Time Decay (Theta) Accelerate or Slow down the Delta’s Movement toward 1.0 as an Option Moves ITM?

Time decay (Theta) accelerates the Delta's movement toward 1.0 (or -1.0) as an option moves ITM, especially as expiration approaches. As time value erodes, the option's price becomes increasingly dominated by its intrinsic value.

This intrinsic value component is what drives the Delta closer to 1.0 or -1.0, making the option behave more like the underlying asset.