Wiki is not always the most reliable of resources, but it's usually reliable enough. Here is an excerpt from RB's wiki page:
Austrian entrepreneur Dietrich Mateschitz was inspired by an existing energy drink named Krating Daeng, which was first introduced and sold in Thailand by Chaleo Yoovidhya. He took this idea, modified the ingredients to suit the tastes of Westerners, and, in partnership with Chaleo, founded Red Bull GmbH in 1987 in Chakkapong, Thailand. In Thai, daeng means red, and a krating (known in English as a gaur or Indian bison) is a large species of wild bovine native to South Asia. Yoovidhya's heirs own majority stakes in both brands, and they both use the same red bull on yellow sun logo while continuing to market the separate drinks to the respective Thai and Western markets
And here is the counterpart excerpt on Red Bull, on Krating Daeng's page:
The Thai product is a different company from the global brand Red Bull as formulated by Dietrich Mateschitz, an Austrian entrepreneur. Mateschitz was the international marketing director for Blendax, a German toothpaste company, when he visited Thailand in 1982 and discovered that Krating Daeng helped to cure his jet lag. He worked in partnership with Chaleo's T.C. Pharmaceuticals to adapt the formula and composition to Western tastes. Red Bull was launched in 1987. The two companies are often mistaken for each other, but they are separate entities focusing on different target markets running in conjunction with one another. Today, Red Bull GmbH is 51 percent controlled by the Yoovidhya family, who own the trademark for the drink in Europe and the United States of America.