Source: Unsplash 

Robinhood said in a post to its corporate blog:

"Our mission at Robinhood is to democratize finance for all. We're proud to have created a platform that has helped everyday people, from all backgrounds, shape their financial futures and invest for the long term.

We continuously monitor the markets and make changes where necessary. In light of recent volatility, we are restricting transactions for certain securities to position closing only, including $AMC, $BB, $BBBY, $EXPR, $GME, $KOSS, $NAKD and $NOK.

We also raised margin requirements for certain securities... We're committed to helping our customers navigate this uncertainty. We fundamentally believe that everyone should have access to financial markets. We're humbled to have helped many people invest in the markets for the first time. And we're determined to provide new and experienced investors with the tools and resources to help them invest responsibly for their long-term financial futures." Reference Link