The only Championship club to pay out less on intermediaries was Hull City who spent £242,986 in the same period.
Fulham were the biggest spenders splashing out over £10 million on agents, more than the club record fee Posh will receive for striker Ivan Toney.
The biggest transfer fee paid out in the relevant period was £1 million on Exeter City forward Joel Randall, although the payments are spread over the length of his contract.