JPMorgan Chase and Bank of America lead all other banks in total mobile users, and also, apparently, in the percentage of mobile-only users — both banks clock in at about 63%. But is this number accurate?

The 63% number comes from a piece by Jim Bruene of NetBanker on banks’ mobile traffic. The data itself was compiled by comScore, which ranks the Top 50 sites by traffic on its site. comScore also breaks out mobile visits from that total traffic figure.

None of the top 50 were banks, and only one was a fintech company (Intuit.) comScore sent NetBanker the data on banks, however, and it yielded some fascinating numbers.

What caught our eye was the following:

• Across all banks, 40% of mobile users are “mobile-only” while 60% also use desktop online banking
• But at BofA and Chase, about 2/3 of their mobile base is “mobile-only”

and

“Only 1/3 of [JPMorgan Chase and Bank of America’s] mobile users went to the desktop during February.”

Leaving aside questions of how the numbers were derived, all we can say is, Wow. And also, Really?

It’s no secret mobile usage is growing, but are customers dropping the desktop this quickly? As Bruene pointed out, a lot of this mobile-only traffic comes from single-service credit card users. But Bank of America has 12.5 million mobile users. Are nearly 8 million of them mobile-only?

Earlier this year Bank Innovation reported Chase’s mobile user base had grown to 12.4 million, so they’re in the same boat.

We reached out to both banks for comment.

Bank of America spokeswoman Tara Burke replied, “I am not familiar with that stat of 1/3. Never heard it before and we don’t break usage by month. We have 12.5 million mobile banking customers. We continue to see an uptick in the number of customers using mobile banking.”

She also sent along a fact sheet on Bank of America’s mobile banking numbers, with the following section on demographics:

• Bank of America Mobile users are spread across a wide range of ages – including a significant portion of users in the 25 – 34 and 35 – 44 age ranges for Mobile web/app users and a significantly higher concentration in the 18 – 24 range for Text Banking (BAC monthly mobile banking/text banking tracker).
• Bank of America’s Mobile users are equally balanced between males and females for Mobile web/app users, but are skewed female for Text Banking (BAC monthly mobile banking/text banking tracker).
• Higher representation in the $50k – $75k income bracket for Mobile app/web customers and $15k – $50k for the majority of Text Banking users (BAC monthly mobile banking/text banking tracker).

As of 11 AM March 28, JPMorgan Chase was still looking into the numbers. We’ll post an update when we hear from them.

Everyone expects the mobile usage numbers to go this way — desktop computer usage, particularly among the young, is expected to decline. It’s just a little shocking that this would happen so fast — so shocking that even Bank of America hasn’t heard about it.