Savantji!
Awaiting ur reply.
Rgds,
Hari
Hi Hari,
For Part 1 of your query the answer is as follows:
Let us say There are five traders: T1, T2, T3, T4 and T5.
On Monday, T1 sells 5 contracts and T2 buys them. This creates an open interest of 5. Later T3 buys 25 contracts from T4. This increases the Open interest from 5 to 30.
On Tuesday, T2 squares up by selling the 5 contracts and T4 buys them. As T2 squares up his position, the OI reduces by 5 and becomes 25.
On Wednesday, T3 also sells his 25 contracts to T5, and squares up his own position.
Therefore, On Wednesday, T3 reduces the OI by 25 but T5 creates additional OI of 25. Therefore the OI does not change and remains 25. This means we should consider the open positions one side only (either long or short) and calculate the OI. Therefore number of Buyers=Number of Sellers does not nullify the trades in opposite directions.
I hope this helps.
_Anant