The bank sold 42.97 billion of the 91-day treasury bill at a 14.18 percent marginal rate, down from 14.80 percent at the previous auction, the regulator said in a statement.

It sold 50 billion naira worth in the 182-day bills at 15.48 percent compared with 15.50 percent previously, and 57.12 billion naira worth of the 364-day instrument at a marginal rate of 15.57 percent versus 15.55 percent at the last auction.

The 364-day papers attracted the highest subscription, with investors bidding for a total of 160.58 billion naira.

Traders said most off-shore investors prefer investing in the longer-dated bills.

Total demand stood at 328.78 billion naira compared with 476.86 billion naira at the last auction.

Nigeria, Africa's second biggest economy after South Africa, issues treasury bills regularly as part of monetary control measures to help lenders manage their liquidity.