LONDON, Aug 11 (Reuters) - One of Diageo's largest shareholders has questioned its decision to sell one of its oldest whiskey brands while buying a tequila company founded by actor George Clooney.
Nick Train, co-founder of Lindsell Train, a fund management group that is Diageo's eighth largest shareholder, told investors in a letter dated August 9 it would be "interesting" to see if the company can integrate Clooney's Casamigos tequila brand with its Don Julio label, bought in 2015.
Diageo announced in June it would buy Casamigos for up to $1 billion.
Analysts have questioned how Diageo will manage its two tequila brands, and whether Casamigos can sustain its high growth.
Train was also critical of Diageo's sale of Bushmills, the Irish whiskey brand it swapped with the owners of Don Julio as part of the 2015 deal.
Diageo announced in January it would re-enter the Irish whiskey market with a new brand called Roe & Co.
"We were sorry to see Bushmills go and then somewhat surprised to see Diageo announce this year it is investing in the creation of a brand new Irish whiskey brand," Train said.
"It'll take some doing to match the 409-year heritage of Bushmills. And, ostensibly, it does not appear consistent."
Train said while he believed Diageo's shares, that make up 10 percent of his 3.9 billion-pound ($5.06 billion) Lindsell Train UK Equity fund, are undervalued, he had raised his concerns with the company.
"There are questions that we and, we suspect, other investors have about the execution of Diageo's strategy," he said.
"Questions that don't necessarily ring alarm bells, but are definitely of the kinds that need having an eye kept on."
Diageo did not respond to a request for comment. ($1 = 0.7713 pounds) (Reporting by Alasdair Pal; Editing by Greg Mahlich)