Square’s Cash App derived half of its fourth-quarter revenue from Bitcoin (BTC) services.

According to a shareholder letter published on Feb. 28, Bitcoin revenue amounted to $178 million during the fourth quarter of 2019, while combined non-Bitcoin revenue totaled $183 million.

In total Bitcoin accounted for more than half a billion dollars of revenue across 2019, equating to around $8 million in profits. That’s up from $1.7 million the previous year.

The figures show that Bitcoin is increasing in popularity with smaller retail investors on the peer-to-peer payments app, with the last quarter accounting for almost 40% of Square's Bitcoin revenue for the year.

Cash App — from Twitter CEO Jack Dorsey’s firm Square — is currently the second most-used finance app on Google Play, and the 23rd-most used app on the platform overall. It also offers fee-free free stock trading for its 24 million active users.

Average crypto spend users doubles in one year

They’re not major players on Cash App however, with each user conducting $7.42 worth of monthly BTC trades on average. Still, that’s twice as much as December 2018, when the average user generated $3.50 in Bitcon trades a month.

Per-person Bitcoin revenue is also growing at twice the speed of the platform’s average, with the average quarterly revenue of customers doubling from $15 to $30 since Dec. 2017.

Cash App’s $8 million in Bitcoin profits account for less than 1% of Square’s total $937 million in gross profits when excluding the company’s $373 million sale of its food delivery app, Caviar.

Cash App promoted by TikTok influencers

Could Tik Tok help explain the increase in Bitcoin turnover in the quarter? In December Cash App targeted a new generation of Bitcoin investors via an influencer campaign on the short-form video-sharing app.

The campaign saw multiple TikTok-based musicians compose songs titled ‘Cash App’, including a track by influencer Shiggy that generated millions of views on TikTok. In total more than 9,600 paid and organic videos were created during the campaign generating 136.5 million views.