SAO PAULO, Jan 12 (Reuters) - Shares in Brazilian retailer Americanas SA (AMER3.SA) fell more than 75% on Thursday after its chief executive officer resigned citing the discovery of "accounting inconsistencies" totaling 20 billion reais ($3.9 billion). Rial attributed the inconsistencies to differences in accounting for the financial cost of bank loans and debt with suppliers. The outgoing CEO said Americanas would likely need a capital increase, though noted he didn't expect a short-term impact from the inconsistencies on its cash position. Analysts at Santander and JPMorgan, who rated Americanas "Neutral" and "Underweight" respectively, also forecast a major negative reaction to the news. PwC, Americanas' auditor, declined to comment on the accounting inconsistencies referred to by Rial.

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