Japanese publisher Tecmo has slammed the new E3 Media and Business Summit as a badly organised "experimental project".
The harsh criticism comes as the event is due to start this week, with format holders Microsoft, Sony and Nintendo all readying conferences for the world's press.
"New show management didn't know what it was doing," vice president of Tecmo, John Inada told GameSpot. "I don't have money to waste on an experimental project," he said.
As well as feeling badly treated by organisers in the past, the lack of retail buyers is another reason the Ninja Gaiden and Dead or Alive publisher isn't interested in attending the event.
"Previously, we were not treated very nicely by the old E3 management, so we didn't feel obligated to cooperate this year," said Inada.
"I also heard that a lot of the [retail] buyers weren't coming this year," he added.