Marketing has learned that Chelsea business affairs director Paul Smith has held extensive negotiations with the mobile brand about replacing Emirates to become its shirt sponsor for three years from the end of the season, with an option to extend.
The football club was seeking a minimum of £6m a year - an increase of £2m on its deal with Emirates - to reflect its new-found celebrity status and the Chelsea brand's global ambitions.
It is understood that the deal with Siemens will be in excess of £6m a year, but it falls short of the £100m 15-year combined stadium rights and sponsorship deal that rival club Arsenal has negotiated with Emirates.
Chelsea has denied that a deal has been completed, with a spokesman insisting final-stage negotiations are ongoing with 'several global blue-chip companies'.
However, sources have said an agreement is imminent.
Siemens Mobile sponsors Spanish side Real Madrid, but its deal expires at the end of this season and it has been suggested it will not re-sign.