Former Network Rail boss Sir John Armitt is preparing to leave the driver's seat at National Express, one of Britain's largest transport groups.
Sky News has learned that the company has instructed talent scouts to identify a long-term successor to Sir John, who has chaired the group since February 2013.
In a statement, a spokesman said: "There are no plans for Sir John Armitt to leave office before his term ends in 2022."
External candidates, as well as existing board members, will be considered by National Express for the position.
The company recently reported strong performance over the three months to September in its UK bus operations and its business in North America, Spain and Morocco.
Sir John's predecessor, John Devaney, was forced to deal with a set of more difficult circumstances, including an activist campaign led by hedge fund Elliott Advisers and a takeover bid involving CVC Capital Partners and the Spanish Cosmen family.
Anyone who succeeds Sir John will have to recruit a replacement for Dean Finch, who has been credited for boosting National Express's improved performance since becoming its chief executive in 2010, unless the latter decides first.
One of the most difficult periods of the pair's mandate came in 2016, when one of the National Express bus services in the US was involved in an accident in which six children died.
The company faced severe criticism from investors the following year for granting Finch an annual bonus of £ 1 million.
Sir John is a veteran of the UK transport and infrastructure sectors, with his biggest jobs including chairing the Olympic Delivery Authority before the London 2012 Olympic Games.
He remains on the board of the Berkeley Group, the home builder.
On Monday, National Express shares closed at just over 2% at 473p, rising about 17% last year.
The company now has a market value of £ 2.37 billion.