LAGOS- Nigeria's state-run oil company saw its revenue decline by 20% to 3.7 trillion naira ($9 billion) in 2020, a year when the COVID-19 economic shock caused the price of oil to crash on global markets, newly released financial statements showed.

The Nigerian National Petroleum Corporation (NNPC) saw its gross profit plummet by 91% to 64.7 billion naira ($158 million) in 2020 compared with 2019, the data showed.

The publication of the statements comes two weeks after President Muhammadu Buhari announced that NNPC had made a net profit of 287.2 billion naira in 2020, saying this was the corporation's first net profit in its 44-year history. 

Buhari provided no further details at the time, while NNPC chief Mele Kyari said in general terms that the group had cut costs, improved efficiency and faced lower borrowing costs.

The detailed statements, audited by three accountancy firms including PwC and published late on Wednesday, showed that the main reason for the net profit figure was 713.4 billion naira ($1.74 billion) in net impairment reversals on financial assets.

A note said the reversals "relate mainly to the recovery of strategic alliance receivable amounts from the Federation and reversal of full impairment on receivables which are no longer doubtful", without explaining further.

NNPC operates joint production ventures with Western oil majors and is also involved in refining and marketing petroleum products. It has released few details of its finances for most of its history.

Anti-corruption campaigners have long asked for NNPC to be more transparent, and last year it published audited accounts for 2019 in what it said was a historical first. ($1 = 410.9000 naira)

(Reporting by Fikayo Owoeye and Libby George, editing by Estelle Shirbon and Elaine Hardcastle) ((estelle.shirbon@thomsonreuters.com))