Maintaining the downward trend, the Sensex at the Bombay Stock Exchange was trading 43 points in the negative territory at 15,897 in late morning deals, when reports last came in.After rallying by over 484 points in the past two sessions, the 30-share index fell by 49 points, or 0.31 per cent, to 15,890, in the first few minutes of trade today.In a similar fashion, the wide-based National Stock Exchange Nifty Index was trading 16 points down at 4,749.