An Austrian regulatory filing published to the corporate registry on Monday shows that the transfer took place on May 20 but did not disclose the reason for the move, who will ultimately control the stake, or where it may eventually be directed, as reported by Bloomberg.

Commenting on the transfer, a Red Bull spokesperson said via email: “Fiduciary solutions such as this are common in order to ensure long-term continuity in large, successful companies.”

Fides Trustees says it works with wealthy families and individuals around the world to revise their personal structures in response to changes in personal and family circumstances.

Chalerm, 74, received the stake around four decades ago when his father, the late Thai tycoon Chaleo Yoovidhya, partnered with Austrian entrepreneur Dietrich Mateschitz to push the brand to the international market.

Chaleo, who was born into poverty in northern Thailand, worked a range of jobs before founding TC Pharmaceutical Industries in 1962. There, he created an energy tonic called Krating Daeng, which means “red bull” in Thai, according to the Wall Street Journal.

The drink eventually caught the attention of Mateschitz in 1982 and the two men teamed up to take it global. Each invested US$500,000 and took a 49% stake in the venture while the remaining 2% went to Chalerm

The Yoovidhyas still hold a 49% stake in the firm, which is estimated to be worth $27.9 billion, based on Red Bull’s performance and peer comparisons.

They were named by Forbes as Thailand’s richest family with a net worth of $36 billion last July.