Key benchmark indices are trading firm in early trade on buying demand in index pivotals. At 9:25 IST, the barometer index, the S&P BSE Sensex, was up 271.94 points or 0.52% at 52,823.47. The Nifty 50 index was up 72.95 points or 0.46% at 15,884.80. Asian stocks are trading mixed.