Sprint Nextel, the third-biggest US mobile phone company, has slowed its capital spending in an effort to boost its free cash flow – a move that could delay the planned commercial deployment of a 4G wireless broadband network based on WiMax technology.

The capital outlay cutbacks, which could also hit Sprint Nextel’s telecommunications equipment suppliers, comes as the company struggles to stem a loss in subscribers and continues its search for a new chief executive to replace Gary Forsee, who resigned under pressure from the board last month.