Allegations surfaced last year that senior executives from both Ma'ariv and Yediot Achronot had been involved in the illegal wiretapping of the offices of each other and of other journalists as well as those of public and political figures.
Nimrodi was also charged with subsequently ordering wiretaps on the phones of his own employees at Ma'ariv.
Nimrodi and Ronen were also charged with trying to interfere with the investigation by allegedly attempting to bribe Friedan and Tsur to keep quiet about who hired them.
The charges against Nimrodi and Ronen came after the two private investigators decided to cooperate with the government.
Charges of conducting illegal wiretaps are also being prepared against Moshe Vardi, the editor of Yediot Achronot.