The all-share index, which rose 50% in 2020, shed 1.8% on Tuesday, the most in one day since December. The index of Nigeria's top 10 banking shares shed 5.3%.
Stocks had been rising since October as local funds moved into equities following two rate cuts last year, and as excess naira flooded money markets due to historically low yields on the debt market.
The all-share index, which rose 50% in 2020, shed 3.04% this week, the most since July 2013. Stocks dropped to 40,439.85 points on Friday, down 1.4% at a one-month low following eight days of losses.
At an open market Treasury auction on Thursday, investors sought one-year yields as high as 13%.