UK's Ofgem tells bidders for National Grid gas networks earnings not guaranteed-SSE

Sept 28 (Reuters) - UK energy regulator Ofgem told potential buyers of a majority stake in National Grid (LSE: NG.L - news) 's four gas networks and part of utility SSE (LSE: SSE.L - news) 's SGN network on Wednesday that price controls for the period after 2021 have not yet been set, SSE said.

Ofgem is reminding bidders that any premium they pay above existing values may not be compensated when Ofgem sets the new price control, SSE said in a statement.

Hong Kong billionaire Li Ka-Shing's Cheung Kong (Swiss: CKH.SW - news) Infrastructure Holdings Ltd is preparing a bid for a majority stake in National Grid's British Gas networks, whose overall value is up to 11 billion pounds ($14.31 billion).

Another major network looking for investors is SGN, which operates in Scotland and southern England. SGN shareholder SSE (Amsterdam: UW8.AS - news) has put up to a third of its 50 percent stake up for sale.

Price controls set the amount of money that can be earned by the companies which operate Britain's networks over a set period of time. The firms recover their allowed revenues by charging suppliers, who in turn pass on the costs to customers.

($1 = 0.7687 pounds) (Reporting by Oleg Vukmanovic; Editing by Adrian Croft)