In remarks during the company's recent Investor's Day webcast, Shawn Moore, VP of assisted tax services, noted the target market is limited by that fact that one of four independents reviewed by Block knowingly commit tax fraud.

But the company has been buying independents, although it did not provide any figures. "We have had a great deal of success already," Moore said. The company has acquired independents for three to four times EBITDA and Block's stock is trading at more than 10 times EBITDA. And driving interest by sellers is the graying of the market. Moore said 65 percent of independent owners are 63 years old or older, echoing the succession problem facing CPA firms.

Moore said Block has advantages as a "reputable, capable" buyer in a market in which owners have trouble selling their businesses. "Prospective buyers are challenged to find financing due to little or no fixed assets attached to the business," he said. Owners must also be careful in choosing buyers since most deals involve one- or two-year trailing contingent payments, Moore continued.

For independents that might become franchises, Block can provide services and products the operators cannot afford to provide, along with strong field management, Moore contended.

Block is also acquiring urban Block franchises. Those were more than 650 stores that were franchised just before 2012. Moore said the company prefers to franchise rural sites and operate those in cities. There are more than 10,000 Block offices with 60 percent of those company owned. The company is not looking to change the percentages.

However, Moore said the Block this year "bought back a significant number of these." He did not provide store numbers.