At 11.28am, the FBM KLCI lost 49.67 points or 2.68% to 1,803.40. Turnover was 2.65 billion shares valued at RM1.95bil.
Decliners hammered advancers almost 35 to one or 1,256 losers to 36 gainers and 119 counter unchanged. This was perhaps the worst for the broader market in many years.
Public Bank was down 78 sen or 3.37% to RM21.20. There were 3.70 million shares done at prices ranging from RM21 to RM21.72.
The decline saw over RM3bil erased from Public Bank's market capitalisation and it was reduced to RM82.45bil.
Public Banks shares have been hitting fresh record highs until last Friday as it was a big beneficiary of the increase in the Overnight Policy Rate two weeks ago.
Several research houses had also raised their outlook for the banking stock due to the firm fundamentals and strong earnings growth.