Let us take a example: Year 2012-2013
Say Last Day i.e. on 31.03.2012 closing Index is 10000 Points and 10%,15%,20% is calculated = 1000,1500,2000
Now for the coming Qtr i.e. April to June,13, if there is change in points of 1000 or 1500 or 2000 comparing to just previous day closing index,then breaker is applied
For example: 2nd April,13 index is closed at 12500 points.
Now for 3rd April,
Movement
10%
|
15%
|
20%
|
Before 1 Pm =1 hr Halt
1 – Before 2.30pm = ½ hr Halt
On or after 2.30 = No Halt
|
Before 1 Pm =2 hr Halt
1 – Before 2.30pm = 1 hr Halt
On or after 2.30 = halt for remainder of day
|
Halt for remainder of day
|
In your question: If market on 3rd April at 12.30 (before 1 pm) mkt falls to 11500 points (i.e. 1000 points down in comparison to previous day index 12500), the market will be get stopped for 1 hr (1 hr Halt). Now after 1 hr when the market opens at 1.30 pm and gradually falls to 11000 around 1.35 pm, NOW we need to compare cumulatively from previous day i.e. 12500-11000 = cumulative fall in points is 1500 (treated as 15% change). The Market now stopped for 1 hr again (see table 15 % slab) till 2.35pm
Now if market again falls to 10500 points [i.e. cumulative fall in points 12500-10500 = 2000 points which is 20 % change)]. Due to 20 % change, now referring to 3rd slab, the market will be suspended for remainder of the day i.e. from 2.35 till till market closing time.
In this way, in our example, Index max to max can go down upto 2000 points.
In a nutshell for your confusion: Don think that 10 % for whole day, always think cumulatively & then decide as per rules tabled above.
Note 10 %,etc always be computed on closing day of last qtr to arrive at points(like 1000 etc), then compare this 1000 etc with previous closing day Index)