In the parallel market, the naira weakened slightly to N1,362 against the US dollar yesterday, down from N1,357 on Monday. 

Conversely, the local currency gained ground in the official Nigerian Foreign Exchange Market (NFEM), strengthening to N1,331.5 per dollar from Monday's rate of N1,332.9—a N1.4 appreciation, according to Central Bank of Nigeria (CBN) data.

As a result of these opposing movements, the spread between the official and black-market rates expanded from N24.1 per dollar on Monday to N30.5 per dollar. 

Meanwhile, trading activity in the official window surged, with interbank transaction volume rising 334.8 percent to $313.6 million, up from $72.12 million logged on Monday.

Source