The roll spread was positive on every session in the record, so the next month cost more
Futures expire, so a position held past expiry has to move to the next month. That move is a roll. For a long position it means selling the near month and buying the next one on the same day. The roll spread is the next settle less the near settle, and it is the price of carrying the position for the extra days.
The chart shows the roll spread, annualised, for the last eleven sessions before each monthly expiry, from 17 Jul 2025 to 25 Aug 2026. It was positive on every session in the record, which is the usual carry shape, because the later month trades above the earlier one.
Roll activity builds before expiry. Open interest moves from the expiring month to the next, and the share left in the expiring month falls. The cost is set by the price gap on the day of the roll, so a roll done earlier or later changes the spread.
The sign tells you who pays. A positive spread means the next month is dearer. A long position pays it when it rolls, and a short position receives it. A calendar spread trades the same pair as one order, so its price is the same carry measured on a single day.
When you measure the cost, include the charges on both legs: STT on the futures sale at 0.05% from 1 Apr 2026, exchange charges, and GST at 18% on brokerage and exchange charges. The deeper pages listed below cover the carry and the roll in more detail.
Before you trade. Derivatives trading carries a high risk of loss. SEBI's study "Profitability of Individual Traders in the Equity Derivatives Segment (FY25 to FY26)" (August 2026) found that 87.7% of individual traders in equity F&O made net losses in FY26, with aggregate net losses of Rs 91,685 crore. Read the SEBI study