The peer-to-peer payments race is now more than a duel between bank-backed Zelle and Paypal-owned Venmo.

According to a report released Thursday from Nomura Instinet analyst Dan Dolev, Cash app downloads grew by 2.2 million in May, up from 2 million in April. Meanwhile, Nomura reported that new downloads of Venmo were up 1.7 million in May. Nomura’s analysis was drawn from its proprietary Cash app versus Venmo tracker tool.

Dolev pointed to a larger trend around Venmo’s slowing new user acquisition. While year-over-year growth for Venmo still outpaces the Cash app at 35% versus 19%, the growth in new app downloads of Venmo has steadily slowed down, compared to increases of 54% in April, 47% in March and 44% in February, the report stated.

Despite the apparent strong growth of Square’s Cash app, the peer-to-peer payments platform still has a long way to go to catch up to Venmo, said Cornerstone Advisors senior director Tony DeSanctis. “I think the bottom line is that the download number is a function of growth rate since Square is so much smaller.”

A better metric to track Venmo’s growth, according to Moshe Katri, managing director of equity research at Wedbush Securities, is PayPal’s success in beginning to monetize it. According to PayPal, Venmo is on a path to generate $300 million in revenue this year through merchant payments with Venmo, fees and the Venmo physical debit card.

“The bigger story is how quickly PayPal has been able to monetize Venmo,” Katri said. “The Square Cash app can have 10 times the number of downloads of Venmo, but what’s really important is how you’re monetizing the user base. Venmo could become a billion dollar business for PayPal.”