An Australian songwriter, who turned tech entrepreneur with a platform to help musicians sell their songs for use in movies, advertising, television and video games and apps, now has an $879 million company on his hands, after raising more than $100 million in a marathon capital raising campaign.

US-based music technology business Songtradr took 18 months to close its latest funding round, finally securing $US70 million ($109 million) in funding at a $US530 million valuation, with Fortnite-maker Epic Games joining its investor roll.