Boeing Co. is in negotiations to sell as many as 500 commercial aircraft to Chinese buyers, according to multiple reports citing people familiar with the matter. The discussions, first reported by Bloomberg, would represent one of the largest single-country orders in the company’s history if completed. The news sent Boeing’s shares up roughly 2.6% in early New York trading on Thursday. Details on the potential mix of models, pricing, and delivery timelines have not been disclosed, and the talks may still fall through, the reports cautioned. Neither Boeing nor Chinese aviation authorities have commented publicly on the negotiations.