Graphic design giant Canva can claw back departing employees’ share rights if they publicly criticise the start-up, via a similar legal structure to one that OpenAI boss Sam Altman apologised for including at his company.

The Australian Financial Review can reveal documents signed by Canva staff give the $US26 billion ($39 billion) start-up the right to invalidate share rights if employees breach strict rules that remain in force even after they leave the company.