The PDP spent N2.9 billion while the APC spent N4.8 billion on the general elections.
According to a report by Premium Times, the nation's two biggest parties submitted their reports to the commission well outside of the constitutionally-required window of six months after the election.
In the filings disclosed by Premium Times, the PDP spent N2.9 billion while the APC spent N4.8 billion on the hotly-contested polls.
APC's audit report was filed by Mai-Alheri and Co. who disclosed that the party derived its 2015 income from the sale of nomination forms which generated N329.5 million, and donations and gifts which generated N275 million.
The APC also spent N296.3 million on administration, N56.5 million on repairs and maintenance, N485,800 million on welfare and N15.4 million on financial charges.
The audit noted that while the party spent N2.9 billion on the 2015 polls, it generated only N604.5 million in the same calendar year, leaving a deficit of N2.3 billion. The party disclosed that this was covered by its surplus from 2014 when it earned about N6.4 billion and spent only N4 billion.
The party also named some fixed assets it acquired including office equipment at N5.1 million, APC Data Centre equipment at N300,000, furniture and fittings at N6.8 million, motor vehicles at N20 million and library books at N3.4 million totaling about N35.8 million.
According to the PDP's audit report, which was executed by Paul Akinade Adebimpe and Co., the party's income in 2015 was derived from donations and levies totalling N200 million and other incomes that amounted to N599.2 million.
While the party spent N4.8 billion on the 2015 elections, it also spent N1.7 billion on administration, N2.8 billion on its national secretariat and N54 million on other financial expenses.
The party had a surplus of N9.4 billion from 2014, as it spent only N3.6 billion from the N13 billion it reportedly earned.
External auditors working for INEC noted that the APC's internal audit system was not properly in place, making it difficult to confidently establish the party's full financial position. The party was also alleged to not possess proper records of fixed assets while also manually executing financial transactions.
In its recommendations to the ruling party, INEC auditors advised that they establish an internal audit and control system, ensure effective monitoring of its fixed assets and computerise the operations of its financial and administrative activities.
INEC's auditors also noted the PDP's failure to prepare a budget for the period under review, an act that could leave room for excessive spending by the party. The party was also noted to manually record financial transactions, a process that could easily lead to errors. The party's fixed asset register was also not maintained for the period under review.
The external auditors advised the party to re-equip its finance unit with an accounting software for effective financial reporting of its transactions as well as prepare budgets that inform spending, and establish a fixed asset register.
Former president, Olusegun Obasanjo, recently alleged that the PDP actually used $3 billion from the government treasury to fund its campaign in the 2015 general elections.
While speaking at a press conference on Thursday, May 10, 2018, Obasanjo, who was president between 1999 and 2007 on the platform of the PDP, said his former party had 'directly or indirectly' used money from government treasury to run the 2015 elections.
He said, "Concluding my point on corruption in politics particularly at the primary elections level, there must be strict control of campaign funding and transparent accounting by the Independent National Electoral Commission (INEC) of all funds contributed and all funds utilised by individuals and political parties for campaigns.
"I was shocked when an insider in the PDP told me that the amount of money the party used for 2015 elections would be in the neighbourhood of $3 billion. It was all directly or indirectly from the government treasury."
The PDP, who was the ruling party in 2015, lost federal power to the APC as then-president, Goodluck Jonathan, was defeated by Muhammadu Buhari of the APC.