Shares in FTSE 100 miner ENRC (LON:ENRC) dropped on Monday as it emerged its founders were set to make a bid for the firm of US$4.7bn - less than a proposal last month.
Alexander Machkevitch, Alijan Ibragimov and Patokh Chodiev along (who each own over 14%) with Kazakhstan's government, want to buy the 46% of the ENRC they don't already own.
The latest deal would pay ENRC shareholders US$2.65 in cash and 0.23 Kazakhmys shares for each ENRC share they hold.
The offer is virtually unchanged from the one outlined in May, but because of a drop in the Kazakhmys share price it is ultimately worth less.
Copper ginat Kazakhmys, which owns 26% of ENRC, backs the bid.
In April this year, the UK Serious Fraud Office said it had begun an investigation into alleged fraud and bribery at ENRC operations, including in the Democratic Republic of Congo.
The group has its roots in the privatisations of Kazakh state assets in the 1990s.
ENRC shares dropped 0.23% to stand at 216.40p.