Nigeria, Sept. 9 -- Nigeria's state-run oil company, NNPC, earned less revenue in 2020 than it did in 2019, but managed to record a historic profit that relied mostly on the reversal of amounts impaired for years, and on income from other sources, its audited statement released Wednesday said.

Impairment reversal is when a company declares an asset valuable after it previously declared it a liability.

The reversal related mainly to its recovery of "strategic alliance" amounts from the federation, the report said without giving further details, while its non-core business income included gain from the devaluation of the naira as well as refunds from the federation for expenses that had previously been written off.

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