Juventus president Andrea Agnelli has questioned Bee Taechaubol's reported €500 million deal to buy 48 percent of AC Milan, saying: "I really struggle to make the sums add up."
An investment group led by Taechaubol has secured an exclusive period of eight weeks during which the Thai businessman can negotiate his acquisition of the club.
Should the deal go ahead at the reported price, that would see the club valued at over €1 billion, and Agnelli expressed his surprise during a news conference held to celebrate Juve's success in winning Serie A, the Coppa Italia and reaching the Champions League final this season.
The Italian businessman said: "The figures as I read them are certainly very impressive, but when I start reflecting on them in greater detail, looking at the net financial position of AC Milan, I really struggle to make the sums add up.
"Of course Milan has an intangible value, the value of the brand, but I do wonder how those figures can lead to a valuation of that kind."
Milan are one of football's most successful clubs, having been crowned champions of Europe seven times, but they have struggled in recent times.
They finished eighth in 2013-14 and 10th last season, but Milan president Silvio Berlusconi told Swiss TV channel RSI suggested his club remain superior to Juve, despite the Bianconeri claiming every one of the last four Serie A titles since Milan last won it in 2010-11.
Berlusconi, who took control of the club in 1986, said: "We will be back winning, and we will be back in Europe. With me, Milan won the Champions League five times; in these years, Juve have only won one out of the five finals they played.
"I can guarantee Milan will become great again. Often it's just a matter of cycles -- our last Scudetto is five years ago."