Indexation
Indexation is a method of adjusting the purchase cost of a capital asset upward for inflation using the Cost Inflation Index, thereby reducing the taxable long-term capital gain and the resulting tax liability under Section 48 of the Income Tax Act.
Indexation recognises that the purchasing power of money erodes over time and that taxing nominal gains overstates the real economic gain realised by the investor. By scaling up the historical acquisition cost by the ratio of current CII to base-year CII, indexation arrives at a higher 'inflation-adjusted' cost, reducing the gain that is subject to tax. The benefit is particularly pronounced for assets held over very long periods in high-inflation environments.
For example, consider a plot of land purchased in FY 2005-06 for ₹20 lakh (CII: 117). If it was transferred in FY 2024-25 (CII approximately 363), the indexed cost would be ₹20 lakh × (363 ÷ 117) = approximately ₹62 lakh. If the sale price was ₹80 lakh, the indexed gain is ₹18 lakh rather than the nominal gain of ₹60 lakh. At a 20% LTCG rate with indexation, tax would be ₹3.6 lakh — far lower than the ₹10 lakh payable on the unadjusted gain.
Budget 2024 significantly curtailed indexation benefits. For real estate, the new regime allows 12.5% LTCG without indexation as the default for properties acquired after July 23, 2024. For earlier acquisitions, taxpayers can compare both options and choose the lower outcome. For debt mutual fund units purchased before April 1, 2023, the prior indexation benefit still applies. Units purchased after April 1, 2023 are taxed as per income tax slab regardless of holding period — a sweeping change that effectively eliminated long-term tax efficiency for new debt fund investments.
Indexation is not available for listed equities, equity mutual funds, or other assets taxed under Section 111A or 112A. For these instruments, the legislature has determined that the concessional flat rates (12.5% and 20%) adequately compensate for the absence of inflation adjustment. The comparison between indexed 20% and flat 12.5% becomes relevant specifically for real estate taxpayers choosing between regimes post-Budget 2024.
A misconception is that indexation always results in zero or negligible gains on real estate. In high-appreciation urban markets, nominal gains can far outpace the CII-based inflation adjustment, resulting in substantial taxable gains even after indexation. In such cases, the 12.5% flat rate (without indexation) may produce a lower tax bill than the 20% rate with indexation — the Budget 2024 amendment precisely addressed this scenario by offering both options.