Attorneys for US Steel argued in federal court Wednesday statements by Cleveland-Cliffs' CEO and the United Steelworkers president were part of a conspiracy to sabotage a merger with Nippon Steel.
Defense attorneys argued what their clients said is protected speech.
District Judge Marilyn Horan said she will issue a decision as soon as possible.
After US Steel put the company on the market, Cleveland-Cliffs offered $7 billion.
But US Steel accepted an offer of nearly $15 billion from Nippon Steel.