Shares in ASX-listed engineering firm Forge Group plunged a staggering 83.6 per cent in a single day after the company emerged from a four week trading halt, compelling it to enter a deal with ANZ which could leave the bank its biggest shareholder.

The company’s shares plunged $3.49 by the close of the Thursday trading session to 68.5 cents, for a whopping 83.6 per cent decline on the back of severe write-downs on two of Forge’s key power station contracts. This single day share decline took roughly $300 million off Forge’s market capitalization,…