The company has promised to underwrite the private sector cost of the lights following a campaign led by Exeter Chamber of Commerce and city centre manager John Harvey to urge the city retailers to contribute to the cost of the lights.
The lights, which cost in the region of £50,000, have previously been funded primarily by retailers with the city council making up any shortfall.
But with the council having to make budget cuts of £2.4 million, it initially said it was unable to contribute this year – although it has now said that it will match fund the private sector contribution.
At the same time, the level of contributions from retailers dropped as pressure from the economic downturn intensified.
Tony Rowe, chief executive and chairman of South West Communications Group said: "Exeter is the leading city in the South West and we can't celebrate Christmas without lights; that is why I'm prepared to support the Chamber in this."
Derek Phillips, vice president of Exeter Chamber said: "While substantial funding has been found, our appeal remains ongoing and we are seeking further support from retailers and business.”