Benchmark indices have extended gains with Sensex and Nifty trading above 26,800 mark and 8,000 levels, respectively.br br Better-than-expected GDP growth rate in June quarter and buying in capital goods shares have buouyed the sentiments among investors.br br By 10:30, the Sensex was higher by 183 points at 26,822 mark and the Nifty gained 57 points at 8,011 levels.