Angry shareholders have vented their frustration at the board and management of struggling data services company Appen, accusing it of “remarkable incompetence” that led to a disastrous decline in value from $4.5 billion to $137 million in four years.

Once a market darling, Appen shares traded at $38 in August 2020 when demand was surging for its services providing clean data sets to companies like Google and Facebook to train their artificial intelligence models.