Clifton Gunderson and LarsonAllen has announced that they will merge effective January 2 and operate under the name CliftonLarsonAllen. The combination of two the top 20 CPA firms in the United States will place the combined entity in the top 10 with combined revenue of more than $550 million annually, more than 500 partners and more than 3,600 professionals. Clifton Gunderson CEO Kris McMasters will oversee CLA LLP, the public accounting practice, while LarsonAllen CEO Gordon Viere will manage the wealth advisory and outsourcing operations.

H&R Block suffered a big setback this week as a federal judge has halted its purchase of 2SS Holdings, the owner of the TaxAct tax preparation software line. The U.S. Justice Department had opposed the deal, arguing that it would violate anti-trust laws. Just over a year ago, Block agreed to buy the smaller company for $287.5 million in cash.

Automatic Data Processing has raised its revenue estimates for fiscal 2012 as the company reported a 9-percent rise in net income on 13-percent revenue growth for the first quarter ended September 30. The company pushed its revenue projections to the top of the previous range for both Employer Services and Professional Employment Organization services.