The trend is to subtract settlements first, then multiply by the percentage of fault for comparative negligence, although some states do these steps in reverse.
Contribution
Contribution is the right of a joint tortfeasor to recover another's portion of the liability for the damages paid to the plaintiff.
The majority and the Restatement Third allow for contribution.
Contribution is the right of the tortfeasor and does not depend upon a judgment being obtained against that person by the plaintiff(s).
Contribution is reduced to the percentage of liability of that defendant in comparative negligence states.
Contribution is not allowed for intentional tortfeasors.
The majority does not allow non-immune tortfeasors to collect contribution from immune tortfeasors.
The majority allows a sued tortfeasor to collect contribution from after the statute of limitations has run.
Contribution can be collected through a cross-claim, impleading, or a separate suit.
A tortfeasor can seek contribution after making a settlement agreement, but he must prove that the other person was a joint tortfeasor and that the settlement was reasonable.