Lawyers from top mergers and acquisitions firms provided tips on some of biggest deals of the last decade to an insider trading ring that made tens of millions of dollars in illegal profits, federal prosecutors said.

Two indictments charging 30 people were unsealed Wednesday in federal court in Boston. None of the firms from whom information was allegedly stolen were identified by prosecutors, but detailed descriptions of the relevant deals indicate they included Wachtell Lipton Rosen & Katz, Latham & Watkins and Goodwin Procter.