After plummeting 34% from its prior peak, the stock index has staged a steady recovery — gaining more than 50% since March, when lockdowns shut down much of the economy.

Stock trading has become easier and cheaper than ever. And people stuck at home during the pandemic have flocked to it. But have venues like Robinhood made it too risky for inexperienced investors?

The electric car maker is now eligible to join the S&P 500 index, which means it would become part of the retirement accounts of millions of ordinary Americans.