Andrew Forrest has dramatically raised his stake in Fortescue Metals Group, as iron ore prices plunge below a critical threshold and cause share prices to flounder.

ASX filings indicate that Andrew Forrest, chairman and ex-CEO of Fortescue Metals Group, bought one million shares in the iron ore miner last week for around $4.9 million, at an average price of $4.93 per share. During the several day period that when purchases were made Fortescue shares fell around…