Sudhanshu Pandey, senior vice-president, investment strategist, FRR, says upswings in the 50-share index should be seen as a selling opportunity as the index may find it difficult to sustain higher levels. Avinnash Gorakssakar, founder director, moneyinvestments.in, says markets are keeping a close eye on the rupee and a level below 55 to the dollar would create panic.