Question: I bought shares in three lots — 100 shares at ₹200, then 150 shares at ₹250 — through my demat account, on different dates. I later sold 180 shares. What cost of acquisition should I use for computing my capital gain, and what does that work out to per share?
Answer: Cost of acquisition = ₹40,000 for the 180 shares sold (100 shares × ₹200 + 80 shares × ₹250), i.e., an average of approximately ₹222.22 per share.

Supporting evidence:
title: incometaxindia.gov.in/768-circular-no.-768-dated-24-6-1998-1
quote: it implies that, out of the existing holdings, the item that first entered into the account is deemed to be the first to be sold out
context: m when securities are held in dematerialised form is that the distinct trail linking every share to a certificate and its unique distinctive number linking it with its subsequent sale is not available.
5.

Section 45(2A) stipulates that in the case of securities held in dematerialised form, for determining ‘date of transfer’ and ‘period of holding’, the FIFO method would be applicable. FIFO method is generally used to determine the value of any item moving out of a stock account and those remaining in stock at any point of time. When applied to an account holding dematerialised stock, it implies that, out of the existing holdings, the item that first entered into the account is deemed to be the first to be sold out. However, once a sale is linked with an earlier purchase, for determination of their ‘date of transfer’ and ‘period of holdings’, Board’s Circular No. 704 would be applica­ble. That is to say that the relevant contract notes as explained in Circular No. 704 will have to be referred to, for ascertaining the cost of the security sold and the date of transfer.
When actually operating an account of dematerialised stock by applying FIFO system, certain other issues can arise. For instance, an investor can hold part of his holdings of a security in physical form and the remaining in dematerialised form. Further, he may hold his dematerialised holdings in more than one account with one or more depositories. In such a situation, there can be doubts whether the FIFO system is to be applied globally on the entire holdings of physical and dematerialised holdings or not. In this connection, it is clarified that :
(
a
) FIFO method will be applied only in respect of the dematerialised holdings because in case of sale of dematerialised securities, the securities held in physical form cannot be construed to have been sold as they continue to remain in posses­sion of the investor and are identified separately.
(
b

) In the depository system, the investor can open and hold multiple accounts. In such a case, where an investor has more than one security account, FIFO method will be applied accountwise. This is because in case where a particular account of an investor is debited for sale of securities, the securities lying in his other account cannot be construed to have been sold as they continue to remain in that account.
(
c
) If in an existing account of dematerialised stock, old physical stock is dematerialised and entered at a later date, under the FIFO meth