There have been rumours about both drivers potentially leaving the team at the end of the season, with Ferrari the name continuing to be linked as question marks remain over their line-up for 2018.
However, following the conclusion of FP1 in Baku where Verstappen and Ricciardo sat top of the standings, Horner told Sky Sports F1 that the talk was nothing more than speculation.
“The drivers are happy,” Horner said.
They’re in good shape, they’re on long contracts. There is no doubt in my mind or anyone in the team’s mind that they’re not part of the team next year. Anything else is just speculation.
“The only driver who had a clause was Mr Vettel. We’re very happy with the drivers and they just want to go quicker.
“They are on junior driver contracts whereas Seb was able to renegotiate after his second world championship which had a bit of performance in it which gave him the trigger when Fernando made his move from Ferrari.
“These drivers don’t have that trigger.”