Online brokerage app Robinhood, which is at the center of a Reddit-fueled rally in a handful of stocks heavily shorted by hedge funds, said on Wednesday it would allow investors to buy fractional shares in GameStop Corp and AMC Entertainment Holdings Inc.

The move allows buying parts of shares, often to encourage participation from smaller investors by reducing the size of the amount they have to bet.

Trading limit on GameStop shares was increased to 100 from 20 on Tuesday, while restrictions on Express Inc, Naked Brand Group Ltd and Nokia were also eased, according to an update on Robinhood's website.

Last week, Chief Executive Vlad Tenev said the app had temporarily curbed some transactions because a clearinghouse had asked for $3 billion in collateral.

The demand forced Robinhood to seek emergency funding from investors who poured in $2.4 billion on Monday, over and above the $1 billion the online brokerage raised last week.

Clearinghouses are intermediaries which ensure the completion of a stock trade even if one side of the deal goes bust.