Change in market lot sizes of 23 securities is effective for F&O Contracts from July 2015 Expiry on wards. The changes in the contracts of these 23 securities were effective from 04 May 2015. From 26 June, they will be first month contracts. Lot sizes of 18 stocks were revised upwards and in 5 stocks the revision is downwards but new lot sizes are not in multiples of old lot sizes.
18 Stocks whose change in market lot sizes with Upward revision
| Sr No | Underlying | Symbol | Present Market Lot | Revised Market Lot |
| 1 | Bank of Baroda | BANKBARODA | 1250 | 2000 |
| 2 | Bharti Airtel Limited | BHARTIARTL | 500 | 1000 |
| 3 | Crompton Greaves Limited | CROMPGREAV | 1000 | 2000 |
| 4 | GAIL (India) Limited | GAIL | 500 | 1000 |
| 5 | GMR Infrastructure Limited | GMRINFRA | 9173 | 13000 |
| 6 | The India Cements Limited | INDIACEM | 2000 | 4000 |
| 7 | Indian Overseas Bank | IOB | 4000 | 8000 |
| 8 | Jindal Steel & Power Limited | JINDALSTEL | 1000 | 2000 |
| 9 | Jaiprakash Power Ventures Limited | JPPOWER | 15000 | 19000 |
| 10 | Just Dial Limited | JUSTDIAL | 125 | 250 |
| 11 | NHPC Limited | NHPC | 10000 | 11000 |
| 12 | Oil & Natural Gas Corporation Limited | ONGC | 500 | 1000 |
| 13 | Punjab National Bank | PNB | 1250 | 2000 |
| 14 | Reliance Communications Limited | RCOM | 2000 | 4000 |
| 15 | Sesa Sterlite Limited | SSLT | 1000 | 2000 |
| 16 | Tata Steel Limited | TATASTEEL | 500 | 1000 |
| 17 | Union Bank of India | UNIONBANK | 1000 | 2000 |
| 18 | Unitech Limited | UNITECH | 9000 | 11000 |
5 Stocks whose new market lot is not in multiple of old lot sizes and revised downwards
| Sr No | Underlying | Symbol | Present Market Lot | Revised Market Lot |
| 1 | Godrej Industries Limited | GODREJIND | 1001 | 1000 |
| 2 | ICICI Bank Limited | ICICIBANK | 1250 | 1000 |
| 3 | State Bank of India | SBIN | 1250 | 1000 |
| 4 | Tata Motors Limited | TATAMOTORS | 500* | 500 |
| 5 | Tata Motors Limited | TATAMTRDVR | 1000* | 1000 |
*As mentioned in Circular no. NSE/FAOP/29271 & NSE/FAOP/29272 dated March 26, 2015, lot size post Corporate action adjustment shall be intimated on 01 Apr 2015 after market hours.
NSE Circular 025/2015 Dated 31 Mar 2015
As per the circular there are another securities whose market lots are revised downwards and in multiples of old lots. So for all contracts changes in these securities were effective from 04 May 2015.
Whenever National Stock Exchange announces change in market lot sizes in the futures and options segment, they are revised in 4 categories.
1) Revised Downwards.
2) Unchanged.
3) Revised Downwards but new lot size is not in multiples of old lot size
4) Revised Upwards
If the lot size is revised downward and in mulptiles of old lot sizes, it can be effective from any date because existing positions of clients can be split accordingly. For example L&T lot size was 250 before 04 May 15. If a client have 1 position in L&T from May 04, after downward revision in lot size, he will have 2 lots (125 lot size*2 = 250). Effecting this change is easy.
But if new lot size is not in multiples of old lot size like in above example, it is not possible to implement the change immediately. Same is the case if lot size is revised upwards. In these two cases, changes will be effective from the expiry of all existing contracts in the market. (At any time, 3 months contracts for each stock is available and this change can be implemented from the date of newly introduced contracts). This is applicable even if the upward revision is in multiples of old lot sizes or not.