App helping to fuel share-buying frenzy allows ‘limited buys’ after a $1bn cash injection to safeguard trades

Shares in companies including videogame retailer GameStop soared again on Friday, as an army of small investors taking aim at Wall Street regained access to amateur share trading platform Robinhood.

The app, weaponised by activist small investors to trap hedge funds in a “short squeeze” that has cost them $20bn on paper by some estimates, had suspended buying of stocks such as GameStop, cinema chain AMC and BlackBerry on Thursday.