Retail investors bought the dip during Monday's stock market plunge

Follow the money: Data from Interactive Brokers, one of the largest retail trading platforms, suggests that their clients saw Monday's selloff as a buying opportunity rather than a reason to get out of the market.

By the numbers: While Interactive Brokers doesn't share day-by-day data, it does provide five-day moving averages.

• The most traded stock last week, Nvidia, saw 83,000 more shares bought than sold on average.
• One day later, the average for the Tuesday-to-Monday period had risen 17% to 97,000 — implying a significant buying spike on Monday alone.

Where it stands: Other popular stocks, like Tesla and Amazon, saw a similar pattern.

• Leveraged tech-stock ETFs like SOXL and TQQQ, which are designed to provide three times the daily stock market return for certain asset classes, also saw their net buying activity rise.

The bottom line: Many retail investors made a lot of money by buying the stock-market plunge of 2020. It seems that lesson has been learned.