Traton warned that its Sept. 10 buyout offer for Navistar, its “best and final offer,” expires at the end of this week.

In a press release and a letter to Navistar’s board of directors, the German company, formed in 2018 out of Volkswagen’s Truck and Bus Group, said its September offer of $43 per share in cash for all outstanding shares of common stock of Navistar not already owned by Traton would expire if not accepted by Friday, Oct. 16, at 6 p.m. Central European Time – that’s noon Eastern Daylight Time in the U.S.

If it’s not accepted by that deadline, Traton said, it will terminate discussions between the companies.

Navistar shares dropped as much as 21% to $35 on the news, according to published reports – matching Traton’s initial offer made in January.

On Jan. 30, Traton submitted a proposal to acquire all outstanding shares of common stock of Navistar at a price of $35 per share, in cash. It increased that on Sept. 10 to $43 per share.

The New York Post reported on Sept. 7 that a squabble on the board could derail the merger, with one member demanding a significantly higher share price than even the sweetened offer.

On Sept. 14, Navistar's board of directors issued a statement saying in had concluded that Traton's revised proposal of $43 per share “significantly undervalues the company and substantial synergies from a combination,” but that “it does represent a starting point for further exploring the possibility of a transaction” and so allowed Traton to conduct due diligence and “engage in further synergy discussions with the company."

In its letter, Traton said, “As we have indicated in our discussions, our findings in due diligence lead us to believe that our price of $43 per share fully values the company. We still believe that this price of $43 per share reflects an extremely attractive premium to Navistar shareholders.

“Therefore, we hereby confirm that $43 per share in cash represents our best and final offer … This proposal will expire and be deemed withdrawn, with no further action on our part, on Friday, 16 Oct. 2020, at 6 p.m. CET, unless prior to that time you have notified us in writing of your willingness to proceed with discussions with a view to entering into a transaction at that price.”

Traton's truck brands include MAN, Scania, and Volkswagen Caminhões e Ônibus. Both Traton and Navistar have taken minority stakes in autonomous-truck-technology developer TuSimple.

In 2016, Volkswagen Truck & Bus took a 16.6% equity stake in Navistar International Corp. as part of a “wide-ranging strategic alliance."