Red Bull are investigating a complaint against their Formula One team boss Christian Horner, the Austrian energy drink company said in a statement on Monday without giving any details about the allegations.
The Briton presided over the most dominant season in Formula One history last year, with Max Verstappen taking his third title in a row and the team winning 21 of 22 races.
"After being made aware of certain recent allegations, the company launched an independent investigation," Red Bull said.
"This process, which is already under way, is being carried out by an external specialist barrister. The company takes these matters extremely seriously and the investigation will be completed as soon as practically possible.
"It would not be appropriate to comment further at this time."
The Times newspaper reported Horner, 50, had been accused of inappropriate behaviour by a female colleague, who complained to the team's parent company.
There was no comment from the team but Horner, who is married to former Spice Girls singer Geri Halliwell, told Dutch newspaper De Telegraaf that he completely denied the allegations.
Sherfane Rutherford struck an unbeaten half-century and Gudakesh Motie produced a brilliant display of spin bowling as West Indies thumped England by 30 runs in a Twenty20 World Cup Group C encounter on Wednesday.
Australia launched their Twenty20 World Cup campaign with a commanding 67-run victory over Ireland in Colombo on Wednesday, powered by four-wicket hauls from Nathan Ellis and Adam Zampa.
Tottenham Hotspur have sacked manager Thomas Frank after eight months in charge, the Premier League club said on Wednesday, after a woeful run of results left the north London club hovering five points above the relegation zone.
South Africa survived Kagiso Rabada's final-over meltdown against Afghanistan and then a double Super Over drama before prevailing in a heart-stopping Group D match of the Twenty20 World Cup on Wednesday.
Pakistan opener Sahibzada Farhan has hit a swift half-century as the 2009 champions comfortably beat the US by 32 runs on Tuesday, clinching their second straight Group A win in the Twenty20 World Cup.