EXPANDING BILL: Nigeria is set to unveil a bank note five times more valuable than its largest denomination bill as part of a major overhaul to its currency.

SHRINKING CURRENCY: Some worry the move will further speed devaluation of the naira and hurt the nation's poorest. The addition early next year of a 5,000 naira note, worth $31.25, comes as the currency has continued its long slide and likely will continue to drop, analysts say.

OLD PROBLEM: Currency troubles have haunted the oil-rich nation for decades. The collapse of oil prices in the 1980s led to unpopular monetary reforms that saw the naira begin its drastic drop in value.