According to the BSE's rules the shares traded on the bourse’s official market have a dynamic price range of 5.0% of the reference price, and the static price range is set at 10% of the last price achieved in an auction. The bourse can expand the price range by up to 30% for a single trading session to prevent suspension of trading.
The Sofia bourse's blue-chip SOFIX index slumped 4.04% to 525.9 points and the broader BG 40 index lost 3.14% to 144.92 by 0940 GMT on Monday.
The markets in Asia and Europe opened strongly in the red on Monday on concerns the global recession will hit earnings.