John Hancock, head of WH Smith USA and a former candidate for the group chief executive position last year, has been moved aside to become chairman of the US operation. Richard McNamara, vice-president of WH Smith USA and its finance director, has left the company altogether.
The company denied the changes implied that managers might have discovered a financial "black hole" in the accounts of the American business.
WH Smith would not comment on the division's trading as the company is due to report its full-year results next month. It claimed the changes had been made to "speed up" the improvements to the American business. Richard Handover, the chief executive, is thought to have been disappointed with the progress the division has been making.
WH Smith also denied that Mr Handover might be deliberately marginalising his challengers for the chief executive position. Mr Hancock will remain in the US and work on "special projects" with Mr Handover, the company said.
"Nothing has gone wrong. There are no holes in the numbers. The changes have been made to make the business work better," a spokesman said.
WH Smith has moved two senior managers from the London head office to take over in America.
David McRedmond, head of the UK travel retail business, takes over from Mr Hancock. Sean Anderson, previously number two to group finance director Keith Hammill, will take Mr McNamara's post.
WH Smith in America is mainly a travel retail operation consisting of hotel and airport stores. It recorded profits of pounds 10m last year on sales of pounds 153m.
Ben Gordon will take over as managing director of UK travel retail for WH Smith. He was previously running the company's "bespoke" business in the US, which sets up stores in casinos and at other leisure attractions.