The Sensex is now down 422 points at 13,378. All index stocks are in the red.HDFC Bank has plunged 7.7% to Rs 1,002. SBI and ICICI Bank have tumbled nearly 7% each to Rs 1,260 and Rs 817, respectively.ACC and Reliance Communications have shed 6.5% each to Rs 1,033 and Rs 419, respectively. NTPC has dropped 6% to Rs 142.Tata Steel, Reliance Energy and Bharti Airtel are down over 5% each to Rs 457, Rs 526 and Rs 601, respectively.Out of 2,551 stocks traded so far, 2,031 have declined, 490 have advanced and the rest are unchanged.Read Earlier Analysis: Selling interest opens up on bourses