Is Four of Pentacles a yes or a no?

This card does not answer cleanly either way. It points to something unresolved, unseen or still in motion, which in practice usually means "not yet" rather than "no".

The Four is holding on: security achieved and then gripped.

Savings, control, a position defended. It is prudence and it is fear, and the card leaves it to you to work out the ratio. Waite's own phrase was "the surety of possessions", and the miserliness reading is a later emphasis rather than the original one.

The picture is unambiguous about the cost even if the meaning is not: every limb is occupied, so nothing else can be picked up without first letting something go.

Yes/no readings are the most popular use of tarot and the one it is worst suited to. A seventy-eight card deck built to describe nuance is being asked for one bit of information, and most of what it knows is discarded in the process.

A more useful version of the same draw: read Four of Pentacles as what shape this takes, not whether it happens. Saving, conserving, holding a position. Sound financial control, and the card genuinely means sound: there is nothing wrong with security.

Also possessiveness, and specifically a grip so tight that nothing can come in either. A closed hand keeps what it has and receives nothing, and the card is describing both effects of the same gesture.

In an advice position it is genuinely double-edged, which is unusual. Sometimes it says hold the line. Sometimes it says notice you have been holding it for years.

Reversed, the lean weakens or inverts. Letting go, spending, opening the hand. Generosity returning after a defensive period.

Or the opposite: financial control lost entirely, where the grip has failed rather than relaxed.

The first is more common and is often a relief. A defence built during a hard period tends to outlast the period, and the reversal is frequently somebody noticing that the emergency ended some time ago.