In a confidential letter to President Goodluck Jonathan dated 25 September 2013 — leaked and published in The Nation on 9 December 2013 — Central Bank Governor Sanusi Lamido Sanusi alleged that the Nigerian National Petroleum Corporation had failed to remit approximately $49.8 billion in crude-oil proceeds for the period January 2012 to July 2013. Subsequent reconciliations between the CBN, NNPC, the Coordinating Minister of the Economy (Ngozi Okonjo-Iweala) and the Revenue Mobilisation, Allocation and Fiscal Commission narrowed the disputed figure to $20 billion by February 2014.
President Jonathan suspended Sanusi from office on 20 February 2014, six months before the natural end of his term, citing 'far-reaching irregularities' in the conduct of the CBN — a suspension widely interpreted as retaliation. Sanusi successfully challenged elements of the suspension at the National Industrial Court but did not return to office; he had emerged the same week as Emir of Kano (see Sanusi deposition story).
The PricewaterhouseCoopers Forensic Audit of the NNPC, commissioned by the Auditor-General for the Federation and submitted in February 2015, confirmed a direct $1.48 billion shortfall attributable to the NPDC (NNPC's upstream subsidiary) on lifted crude. PwC questioned a further $18.5 billion in arrangements — strategic alliances, offshore processing agreements, modified carry agreements and pioneer-status tax holidays — as either non-transparent, contractually irregular, or constituting an effective subsidy to NPDC at the expense of the Federation Account. The PwC report was withheld from public release until April 2015, after the Buhari administration came in, and was a foundational document in the subsequent unbundling of NNPC under the Petroleum Industry Act 2021.