After adding an incredible 37 million subscribers in 2020, Netflix's (NFLX 1.53%) growth has slowed dramatically in 2021. The streaming-TV giant added just 5.5 million subscribers in the first half of 2021 and less than 2 million in Q2. But investors are hoping for a reacceleration in the company's subscriber growth in the second half of the year.

Fortunately, a reacceleration in Netflix's subscriber growth is likely.

A chalkboard sketch of a bar chart with an arrow highlighting a growth trend.

Image source: Getty Images.

Why did subscriber growth slow in the first place?

It doesn't take any complicated analysis to realize why Netflix's subscriber growth slowed during the first half of the year. It boils down to the fact that Netflix saw a pull-forward of demand in 2020 as consumers were sheltering at home amid COVID-related lockdowns.

The company's 37 million net subscriber adds in 2020 were way above Netflix's typical growth rates. In 2019, for instance, Netflix added 28 million subscribers. So when the global economy started reopening and resuming some normalcy in 2021, it made sense that subscriber growth would cool off. Compounding problems, Netflix's original content production paused at one point during 2020, delaying new content that was slated for early 2021. And even when production resumed, it didn't resume at full speed. Instead, it had to ramp up.

"The extraordinary events of COVID-19 led to unprecedented membership growth in 2020," Netflix management explained in the company's first-quarter shareholder letter, "as it pulled forward growth from 2021, and delayed production across every region. In turn, we ended 2020 with a bigger membership and revenue base than we would otherwise have had..."

Netflix's Q3 subscriber growth: what to expect

But with this pull-forward of demand fading further into the past, it stands to reason that Netflix will probably start returning to more normalized patterns of subscriber growth.

Indeed, Netflix guided for 3.5 million net new subscribers in Q3. While this is still below the 6.8 million subscribers the company added in the third quarter of the more normal 2019, it marks a steep acceleration over the approximately 1.5 million net new members added in the second quarter of 2021.

Netflix management provided some useful context in the company's second-quarter shareholder letter, noting that if it achieves its guidance for 3.5 million net new subscriber adds in Q3, it will have added over 54 million members over the past 24 months, or 27 million on an annualized basis; this, management noted, is consistent with the company's pre-COVID annualized run rate of member additions.