2019 was a year of record-highs for the stock markets, and millennials investors weren’t sitting on the sidelines.

According to TD Ameritrade Investor Movement Index (IMX), the most popular stocks net bought by millennials in 2019 were Microsoft (MSFT) and Tesla (TSLA).

Both stocks outperformed the market significantly. But it’s the way millennials traded TSLA throughout the year that was particularly impressive.

“They were buyers of Tesla early in the year, month after month,” TD Ameritrade Chief Market Strategist, J.J. Kinahan said on Yahoo Finance’s On the Move. “They were sellers of it in December. And so that worked out well.“

TSLA spent most of the year underperforming the S&P 500, tumbling during the first five months of the year. By purchasing shares regularly, these millennial traders were able to lower their average cost (Read about dollar cost averaging here.), making their percentage gains that much stronger when Tesla shares rebounded during the second half of the year.

For net sold, Alibaba Group (BABA) topped the list of stocks millennials looked to unload while Facebook (FB) was the biggest net seller among the total client group. Both outperformed the markets.

And an area that Millennials really got walloped? Cannabis stocks.

But Kinnahan said even seasoned investors make bad trades.

“Let's be honest, people are going to make mistakes,” Kinnahan said. “One of the things that millennials may get knocked for is they were by buyers of cannabis stocks.”

He added that younger investors need to consider their time horizons.

“If you're a millennial and you say, ‘I think in the next 10, 15 years, this is going to be legal across the United States.’ There's great potential there. If you're in for the in-and-out play, it probably didn't go really well. And I think that's one of the things people have to decide when they go in anyways.”

Yvette Killian is a producer for Yahoo Finance’s On The Move.

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