Bidders are believed to have lodged first-round offers last week for two power stations put up for sale by the FTSE 100-quoted company.
BG’s Ballylumford plant in Northern Ireland is expected to fetch £300m while the group’s 50 per cent stake in the Seabank plant in Bristol could make £150m.
Bidders are thought to include Japanese firms, while rival UK business Scottish and Southern Energy has pre-emption rights over Seabank.
BG Group recently defended its chief executive Frank Chapman’s £28m pay package ahead of a vote on remuneration by shareholders at its annual shareholder meeting next month.
Although his basic salary and bonus came to £2.7m, the bulk of Chapman’s haul came from vesting £15.5m of paper options accrued over a decade.