Are car dealers incentivized by the date the deal is signed or the date the car is delivered (need answer fast)?

Is there any incentive for a new car dealer to cut a deal before the end of the calendar year for a car which has not arrived on the lot yet (and might not arrive for a month or so)? Mrs. Martian is convinced that astounding deals are to be had this weekend; I always thought that only applied to cars that are already in the dealer inventory (on the lot), not those in transit or on order.

Or is the whole “make our year end numbers” just an urban legend?

(I think this has a factual answer but mods can move if appropriate.)

This is second hand information (I hired an accountant from a major chain of dealerships and she told us a lot of stories) but at that time the manufacturers offered bonuses based on MONTHLY volume or cars sold, not the annual.
I would assume the “marketing year” if it exists is from September to August not the calendar year.

My question is do they get credit in month X for deals that are signed in month X but the car is not delivered until month X+1 (or X+2)? Or only for cars delivered in month X?

IANA automobile dealer, but I know in many industries the manufacturer gives credit when the order is signed. But as @Mighty_Mouse says, there’s a manufacturer incentive pretty much all the time.

The “best time” for a dealer to make its own deal is right before they have to report the inventory on their lot for tax purposes. That’s going to vary by state. Around here it’s late January. Well run dealerships that manage their inventories carefully throughout the year may not care as much about that as the ones that are hanging on by a thread.

Based on my experience with buying a Tesla (so other dealers may do it differently) it is based on the quarter the car is delivered. However that might have been the incentive to the salesman and not the dealership itself.