Popular online trading platform Robinhood says it has lined up $3.4 billion to help meet its funding requirements. The capital injection comes amid a spike in trading on Wall Street fueled by small investors driving up shares in GameStop and other stocks. Robinhood said Monday that Ribbit Capital and several other venture capital firms are providing the funds. The $3.4 billion figure includes $1 billion in funding that Robinhood announced Friday. It needed the funding infusion in order to meet deposit thresholds required by the clearinghouses that handle the trading orders placed by investors on brokerages like Robinhood.