This file combination photo displays logos for AT&T, left, and Deutsche Telekom AG. (Seth Perlman/Roberto Pfeil - AP) Opponents of AT&T’s $39 billion bid for T-Mobile are finding hope in a court decision this week blocking another merger — between H&R Block and a tax software company.

Some antitrust watchers point to similarities in the cases: The tax deal would combine the second largest company in that space with 2SS Holdings, the maker of TaxACT software.

The market concentration created by the combination of identical businesses wouldn’t uphold competition laws, the judge decided.

Judge Beryl A. Howell of the U.S. District Court for the District of Columbia sided with the Justice Department, which sued to block the tax companies’ merger. Beryl’s findings haven’t been publicly released but some antitrust experts and public interest groups say the decision bodes poorly for the wireless megamerger.

“The judge in the H&R Block case ruled that one of the largest companies in a competitive industry could not buy out a competitor, particularly when that competitor is seen as a maverick within that industry,”said Harold Feld, legal director for public interest group Public Knowledge.

The Justice Department’s suit against AT&T and T-Mobile is being reviewed Judge Ellen Huvelle of the same U.S. District Court.

Related:

Justice Department sues to block AT&T, T-Mobile

Sprint Nextel sues to prevent wireless megamerger