This incentive isn't actually listed or advertised anywhere on Acura's website, but Motor Trend's Intellichoice affiliate (ownership cost and value analysis site) managed to uncover the discount. If you bought a completely base NSX, the price could be as low as $139,300 now. That's before you do any other negotiations with your dealer to lower the price further.
The discount only applies to 2019 model year cars, which is actually a great thing. Acura made a bunch of small, important changes to the refreshed NSX for 2019 you can read about here. It's a better car than before, and now it's significantly cheaper than last year's model, as well. That makes the supercar a veritable steal.
Acura has reportedly had this discount in effect since mid-March, and sales throughout this year have been improved versus last year — 72 NSXs had moved off lots at this time in 2018, whereas 102 have found new owners this year. That may not seem like a whole lot, but even a small uptick in supercar sales is meaningful when you're selling in such low quantities. The 2018 calendar year was the worst year in new NSX sales to date, with only 170 in total finding new homes. In 2017 Acura moved a grand total of 581 NSXs, the car's best year.
If you want to actually take advantage of the discount (we envy you) then know it's scheduled to last through March 31, 2020. That's a long time to decide if you want the Japanese supercar. A 992 911 Carrera 4S ($121,660) with a few pricey options will easily be bumping into a base NSX, so your expensive sports car decision just got a little tougher.