NIGERIAN CURRENCY FIRMS AT LATEST AUCTION The Nigerian naira firmed 2.6 pct against the dollar after 17 banks were disqualified from bidding at today's weekly foreign exchange auction, the central bank said. The naira finished at 3.8050 to the dollar, against 3.9050 last week. Only 38.39 mln dlrs of the 50 mln dlrs on offer was sold, with all 27 bidding banks successfully obtaining hard currency. The effective rate, including a central bank levy, for transactions in the coming week, was 3.8241 against 3.9246 last week. The failure to sell the whole allocation was due to the central bank's unprecedented disqualification of 17 banks as punishment for inadequate documentation in previous transactions. Banks are required to submit proof that their bids are based on valid commercial transactions and the central bank has complained in the past that many are failing to produce the right paperwork within the specified time.