"We wanted to win which is what we did," said Cobb, who will retire from his job on July 31. Cobb explained that he came out of retirement six years ago to lead the tax services company and it is a good time to step aside for a new leader. When he took the job, he was the fifth CEO in five years.

Cobb also noted that another important accomplishment was "We got our DIY business back on track."

In a year in which the number of tax returns field fell nationally that did not translate into returns growth. However, Cobb said he was pleased that despite some aggressive promotions, Block held revenue flat. With costs controlled—operating expenses dropped by 3.5 percent—net income reached $408.9 million for fiscal 2017, an increase of 8.5 percent from $374.3 million the prior year. Revenue of $3.04 billion was down by under 1 percent from the fiscal 2016 total.

Despite the market for free returns, which Cobb said are here to stay, the company was able to attract higher-paying clients in other segments of the tax preparation market. Block also said its "Get Your Taxes Won" marketing campaign was highly successful as was its alliance with IBM, whose Watson computer played a major role in the message.

The company is looking at CEO candidates inside and outside the company. Corporate counsel Tom Gerke, who has CEO experience, will serve as interim CEO. Gerke drew high praise from Cobb, who said the company has a strong management team awaiting the new leader.