What happened

Lyft (LYFT 1.08%) stock underperformed a booming market last month, shedding 11% compared to a 3% spike in the S&P 500, according to data provided by S&P Global Market Intelligence.

The decline capped a difficult year for shareholders, with the ridesharing platform's stock down 45% since its initial public offering in March.

A man hails a ride in a city.

Image source: Getty Images.

So what

December's swoon came as Wall Street worried about rider volumes peaking thanks to saturation in established markets and a less-aggressive promotion pace for Lyft and peers like Uber. Those difficult selling conditions could complicate management's plan to reach profitability by late 2021.

Now what

CEO Logan Green and his team will get an opportunity to update that earnings outlook when Lyft announces its fiscal fourth-quarter results on Feb. 11. Executives said back in October that sales should rise by about 47% for the period, which would translate into 66% growth for the full year. The stock's trajectory in 2020 will be heavily influenced by the path that Lyft's expansion pace takes from there, and whether the growth stock can demonstrate an ability to generate profits in a tough industry.