The Volkswagen Group finally looks set to take over U.S. truck and bus manufacturer Navistar International (formerly International Harvester) after the German giant improved the offer it made in September.

VW’s truck and bus holding company, Traton SE, already holds a stake of 16.8 percent in Navistar. On October 14 it made an offer of $44.50 per Navistar share, which means the world’s biggest carmaker is willing to pay over $3.7 billion to acquire the remaining stake of 83.2 percent, valuing the U.S. company as a whole at around $4.4 billion.

In September, Traton offered $43 per share, but Navistar International’s board of directors rejected the bid on grounds that it significantly undervalued the maker of medium- and heavy-duty trucks and buses. Now, however, the two have reached an agreement in principle for the Traton to acquire by merger all remaining shares in Navistar.

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“Following discussions between Navistar and Traton, Navistar’s Board of Directors confirmed that it would be prepared to move forward with a transaction in which Traton would acquire Navistar for $44.50 per share in cash,” the Illinois-based company said in a press statement. In a letter to Traton, Navistar’s board asked the VW-owned company to confirm that a price of $44.50 per share is a basis for finalization of definitive agreements, adding that the offer has the support of its two largest shareholders.

“We are pleased to have reached agreement in principle for a transaction after intensive negotiations with Navistar. We are looking forward to completing our due diligence and obtaining the necessary approvals in respect of this exciting deal in order to welcome the new Traton family member,” said Matthias Gründler, CEO of Traton SE.

Traton is a holding company owned by Volkswagen AG which includes the MAN, Scania and Volkswagen Caminhões e Ônibus brands. If the deal goes through, Navistar International will add three new brands to Traton’s portfolio as the U.S. holding company owns the International Truck, IC Bus, and Navistar Defense brands.