Why isn't spiking the football intentional grounding?

Question

I understand that spiking the football is a time management technique in American football, but I don't understand why there is no penalty (e.g. intentional grounding) associated with it?

Answer 1

This is actually a special rule case.

Section 2 Intentional Grounding

Item 3: Stopping Clock A player under center is permitted to stop the game clock legally to save time if, immediately upon receiving the snap, he begins a continuous throwing motion and throws the ball directly into the ground.

So you may spike the ball to stop the clock if you do so immediately after receiving the ball. However:

Item 4: Delayed Spike A passer, after delaying his passing action for strategic purposes, is prohibited from throwing the ball to the ground in front of him, even though he is under no pressure from defensive rusher(s).

Thus waiting to do so is considered intentional grounding.

Answer 2

Because it's specifically permitted by the intentional grounding rule.

Rule 8, section 2, article 1 of the NFL Rules:

Item 3: Stopping Clock. A player under center is permitted to stop the game clock legally to save time if, immediately upon receiving the snap, he begins a continuous throwing motion and throws the ball directly into the ground.

The NCAA has a similar rule (rule 7, section 3, article 2 of the NCAA rules):

ARTICLE 2. A forward pass is illegal if:

(snip)

e. The passer to conserve time throws the ball directly to the ground (1) after the ball has already touched the ground; or (2) not immediately after controlling the ball.

So spiking is legal only if the snap was not fumbled, unlike the NFL.