"With all the talk about bitcoin, a good deal of people are also starting to open accounts where they can buy and sell crypto-currencies," Bespoke Investment Group said in a Friday blog post.
Schwab reported in mid-November it had 10.6 million active brokerage accounts in October, up 5 percent from the same period last year.
In contrast, Coinbase had 11.7 million users at the end of October, according to data compiled by Alistair Milne, co-founder and chief investment officer of Altana Digital Currency Fund. That's up 148 percent from 4.7 million a year ago.
Through Sunday, that number had grown to 13.3 million, according to Milne's data. That was after an increase of 300,000 users in the last week alone.
Coinbase is the leading platform through which Americans buy digital currencies bitcoin, ethereum and litecoin. Schwab is the second largest broker-dealer by assets under management, according to Investopedia. Fidelity ranks first.
A representative from Schwab did not immediately respond to a phone call and emailed request for comment.
Source: Schwab report, Alistair Milne analysis of Coinbase data. Blanks denote months with no data.
Bitcoin topped $9,000 for the first time over the weekend, taking only a week to add $1,000, helped by a surge of investor interest around the Thanksgiving holiday and Black Friday shopping event.
The digital currency hit an all-time high of $9,732.76 Monday morning, according to CoinDesk, and was trading near $9,580 in the afternoon.
To be sure, comparing Coinbase to traditional stock brokerages is not exactly apples to apples.
Coinbase's website says the company has exchanged more than $50 billion in digital currency. The market value of bitcoin was around $160 billion, slightly more than that of General Electric.
In contrast, Schwab's total client assets were a record $3.26 trillion at the end of October.
Fidelity had 24.9 million brokerage accounts at the end of June, according to the latest available data on the company's website. Total customer assets were $6.2 trillion.
But the key for bitcoin is its stunning pace of growth. Coinbase has more than doubled the number of its users in 12 months. If that pace keeps up, the company will have at least 26.6 million users next November, more than Fidelity had this summer.
"Yes, Charles Schwab has a lot more assets in its accounts than Coinbase users, but the idea that crypto-currencies users are just a fringe part of the financial universe is not accurate," Bespoke said in the post.
The world's largest futures exchange, CME, is planning to launch bitcoin futures in the second week of December. The move will mark another step toward legitimizing a digital asset that was once only the focus of some cryptocurrency developers.