The chairman of Teva Pharmaceutical Industries has purchased 1 million U.S.-listed shares of the world's largest generic drugmaker, the company said on Friday.

Board Chairman Phillip Frost bought the shares on Wednesday, the first day of trading on the New York Stock Exchange. Previously, the U.S.-listed shares of the Israeli company traded on Nasdaq.

Frost bought shares at prices ranging from $37.82 to $39.57, according to the company. The shares were up 0.5% at $39.38 on Friday, moving into positive territory after Teva announced Frost's purchase.

"This investment is simply a reflection of the strength of my conviction regarding Teva's bright future," Frost said in a company-released statement.

Teva, which has a market value of about $38 billion, recently installed Jeremy Levin, a former executive at Bristol-Myers Squibb, as its new chief executive.