Eire Born Spirits, which owns and promotes MMA fighter Conor McGregor's Proper No Twelve Irish Whiskey, has a valuation of around €200m, based on a recent transaction.
The owner of Jose Cuervo Tequila, Becle SAB de CV, spent 1,531m pesos (€58.3m) when it acquired an additional 29pc stake in Eire Born Spirits, according to its recent quarterly results.
Becle, which controls Proximo, the owner of Bushmills whiskey, already had a 20pc stake in the business and completed the exercise of its option to acquire more of Eire Born Spirits, which is owned by McGregor.
Proper No Twelve launched in September 2018, initially in Ireland and the US. The brand, which is now also available in the UK and Australia, sold out a six-month allocation in its first 10 days.
Last month, during Becle's second quarter earnings call, Michael Keyes, chief executive of Proximo Spirits, said Proper No Twelve was "probably the fastest growing whiskey brand".
"Thirty four percent of the [Irish whiskey] category's growth is being driven right now by Proper No Twelve, and you guys can get some information," he said.
"If you look at Nielsen [a retail sales data provider], the last 52 weeks, the brand sold over 40,000 nine-litre cases. And you can look at the math there - Nielsen makes up about 25pc or 30pc of the spirits' overall category. So you can get to a reasonable assumption on volume.
"But it's a great brand, it's dynamic, our partners are great partners, and they have helped us aggressively promote this wonderful product."
A report by IWSR Drinks Analysis found that Proper No Twelve had sold 213,800 cases last year, an increase from 38,200 in 2018. It became the fourth most popular brand globally, behind top-selling brand Jameson, Tullamore Dew and Bushmills.
According to the report, 11.93 million cases (143 million bottles) of Irish whiskey were sold globally in 2019, an increase of 10.6pc on 2018.
In the US, the largest market for Irish whiskey, accounting for more than five million cases, the gap between Scotch and Irish whiskey decreased by a further 446,000 cases in 2019. This reduced the overall gap to 3.8 million cases, a gap which industry body the Irish Whiskey Association said the industry should seek to eliminate this decade.
Sales of Irish whiskey in the domestic market increased only marginally, by 1.5pc, last year, with sales of premium-and-above priced Irish whiskey increasing by 10.4pc from 75,000 cases to 82,800 cases (994,000 bottles).
The premium-and-above price segments now account for 14pc of all Irish whiskey sales in the Irish market.
Proximo declined to comment. An attempt to contact an agency representing Conor McGregor and another for Proper No Twelve resulted in no response at the time of writing.