John Nitti, who had been one of the top media buyers as chief investment officer worlsdies at ZenithOptimedia, has joined Verizon as chief media officer.

Verizon is a ZenithOptimedia client.

Nitti joined Zenith in 2009 as head of the agency’s digital media arm and increased digital billings from $3 million to $180 million. He was promoted to president of activation, in charge of buying all media, in 2012.

The Agency handles media investments totaling more than $10 billion.

Zenith has not yet named a replacement for Nitti.