The new year is just over three weeks old, but that hasn't stopped certain stocks from turning up the heat. Just since the new year, shares of Twilio (NYSE:TWLO) and Cirrus Logic (NASDAQ:CRUS) have racked up double-digit percentage gains very quickly, and they are likely to maintain their impressive momentum for the remainder of 2021 thanks to a variety of growth drivers.

Let's see why investors are so upbeat about these tech stocks early in the new year.

TWLO Chart

TWLO data by YCharts

The iPhone 12's momentum is boosting Cirrus Logic

Cirrus Logic's fortunes are closely tied to Apple (NASDAQ:AAPL), as the iPhone maker accounts for more than 80% of the chipmaker's revenue. The iPhone 12 models are equipped with Cirrus' audio chips, according to iPhone teardown reports. Not surprisingly, the initial success of the iPhone 12 has turned out to be a big tailwind for Cirrus Logic.

JPMorgan analysts' estimates suggest iPhone 12 demand was outpacing supply in December 2020. The lead times from sales to delivery of the iPhone 12 Pro and the Pro Max were as long as 27 days across several markets. This strong response has led Apple to increase the production of its latest devices. According to supply chain sources tapped by Nikkei, Apple is planning to make 96 million iPhones in the first six months of 2021, a 30% spike over the year-ago period.

What's more, Apple is reportedly looking to build as many as 230 million iPhones throughout 2021 -- a nice jump over last year's estimated shipments. All these numbers bode well for Cirrus Logic as the company expects a nice acceleration in its financial results after the arrival of the iPhone 12.

Hand drawing stock chart return.

Image source: Getty Images.

The chipmaker's revenue for the first six months of fiscal 2021 (ended Sept. 26, 2020) declined nearly 6% year over year. However, Cirrus expects its top line to jump 23% year over year to $460 million in the recently concluded third quarter.

More importantly, Cirrus Logic can sustain its newly found momentum. We have already seen that Apple is anticipating strong demand for its 5G smartphones throughout the year, and it can achieve its lofty shipment targets thanks to a clutch of favorable factors. For instance, Apple is expected to corner a nice chunk of the rapidly growing 5G smartphone market this year, so it may have to produce more iPhones in 2021 than last year to meet the booming demand.

Analysts are expecting a mid-single-digit increase in Cirrus' revenue for fiscal 2021 that ends in March 2021. But the chipmaker can surpass those expectations if Apple indeed raises its iPhone production significantly in the first half of the year as supply chain sources indicate, making Cirrus an attractive 5G stock to buy right now.

Twilio's terrific run will continue in a post-COVID-19 world

The novel coronavirus pandemic sent Twilio stock soaring in 2020. Shares of the cloud communications specialist more than tripled last year as there was a jump in the number of organizations shifting to cloud-based contact centers in a bid to remain in touch with customers. Twilio is expected to close 2020 with a top-line jump of 48% over the prior year on the back of pandemic-driven gains.

Analysts expect the good times to continue in the new year as well. Twilio's revenue is expected to increase 32% in 2021, giving investors confidence about the company's business in the new year. However, Twilio can better Wall Street's expectations as it operates in a fast-growing space.

One reason why Twilio won't be running out of steam anytime soon is that its addressable market is expected to increase substantially in the coming years. The company's total addressable market stood at $62 billion in 2020, up from $45 billion in 2017. By 2023, Twilio estimates that its total addressable market can hit $87 billion.

But the good thing about Twilio is that it keeps taking steps to increase its revenue opportunities. In November 2020, Twilio completed the acquisition of Segment -- a customer data platform provider. That move helped Twilio instantly boost its addressable market by $17 billion, which means that the company's overall addressable market will exceed $100 billion in the next couple of years.

All of this means that there is a big, big opportunity available for Twilio to tap into, as its trailing-12-month revenue of $1.54 billion indicates. Of course, Twilio's future success depends on its ability to hold on to existing customers as it brings new ones into its fold. Twilio is doing well on that front as well, as its dollar-based net expansion rate shows us.

Twilio's dollar-based net expansion rate chart.

Chart showing consistent expansion in Twilio's dollar-based net expansion rate. Note: Q1 2020's 143% figure includes revenue from the SendGrid acquisition, which closed on Feb. 1, 2019. Excluding the contribution from SendGrid, the dollar-based net expansion rate would have been 135%. Image source: Twilio.

The company consistently clocked a 130%-plus dollar-based net expansion rate in the first three quarters of 2020. An expansion in this metric means that Twilio's customers are either increasing their spending on the company's services or are buying additional products. Segment's acquisition will help Twilio maintain the impressive growth in this metric as it now has a new product to offer to its existing active customer base of more than 208,000.

Twilio looks well-positioned to keep up its high rate of growth in the new year and beyond thanks to fast-growing end markets and its ability to generate higher spending from customers -- making it an ideal pick for investors looking for a hot growth stock.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.