This is coming as Governor Adams Oshiomhole of Edo State accused the corporation of unilaterally spending N3.8 trillion within the period.
Governors Abdulaziz Yari (Zamfara), Oshiomhole and Nasir el-Rufai (Kaduna) briefed State House correspondents after the meeting which took place at the Council Chamber of the Presidential Villa, Abuja.
Yari said the council received report on the state of funds and the economy from the Director of Funds, Office of the Accountant General of the Federation, Mr. M.K. Dikwa, and after an exhaustive deliberation, resolved to set up the probe committee.
The committee is made up of el-Rufai, Oshiomhole, Governor Ibrahim Dankwabo of Gombe State and his Akwa Ibom State counterpart, Udom Emmanuel.
Yari said: "We have gotten the report from the Excess Crude, what is there and what is not there. Also, the council got the briefing on the unremitted funds by NNPC.
"On that line, a four-man committee of Edo, Gombe, Kaduna, Akwa Ibom (governors) was constituted to go through the books of NNPC and excess crude as well as the Federation Account.
"The four-man committee will check the books of NNPC, most especially the issue of excess crude and what is not remitted into the Federation Account."
In his contribution, Oshiomhole said that NEC discovered that from 2013 to May 2015, NNPC earned $8.1 trillion but paid $4.3 trillion into the Federation Account while spending the sum of $3.8 trillion without being appropriated during the period.
Noting that Monday's NEC was the first time the president had directed NNPC's books to be thrown open, he said: "We are talking about transparency, we are talking about change and what we saw from those numbers, I believe that Nigerians are entitled to know, is that whereas the NNPC claimed to have earned N8.1 trillion, what NNPC paid into the Federation Account from 2012 to May 2015 was N4.3 trillion.
"What it means is that NNPC withheld and spent N3.8 trillion."