BacktestIndia: Free Tax-Aware Backtesting Tool for Factor Investing on NSE Stocks (18+ Years Data)

What Is BacktestIndia? (And Who Is It For?)

Direct Answer: BacktestIndia is a free, web-based platform that simulates how rules-based factor investing strategies would have performed on NSE-listed Indian stocks over the past 18+ years. You define a strategy by selecting factors (like low volatility, momentum, or ROE), set your parameters, and the engine replays history — buying and selling stocks at each rebalance date, deducting real transaction costs, slippage, and India-specific LTCG/STCG taxes. The output tells you exactly how much wealth the strategy would have created after all costs.

Unlike options backtesting tools (algo trading and options-focused platforms) or technical analysis platforms (charting and rule-based trading tools), BacktestIndia focuses exclusively on factor-based equity investing — the same systematic approach used by institutional investors, pension funds, and smart beta ETFs worldwide.

BacktestIndia is built for:

• Self-directed equity investors who want to test "buy low volatility" or "buy high momentum" strategies before committing capital
• Factor investing learners exploring systematic strategies as an alternative to discretionary stock-picking
• Tax-conscious investors who need to understand the real after-tax impact of different rebalancing frequencies
• Finance students and researchers studying quantitative investing in Indian markets
• SEBI-registered advisers who want to illustrate factor strategy performance to clients with tax-aware projections

The Problem: Why Indian Investors Need a Tax-Aware Backtesting Tool

Most retail investors in India face three critical gaps when evaluating systematic strategies:

Gap 1: No Tax-Aware Backtesting Exists

India's capital gains tax structure creates significant drag on active strategies. Short-term gains (holdings under 1 year) are taxed at 20%, while long-term gains are taxed at 12.5% with a ₹1.25 lakh annual exemption. Yet virtually every backtesting platform — global or Indian — shows only pre-tax returns. This means a strategy showing "15% CAGR" might actually deliver 11-12% after Indian taxes, depending on turnover. Without tax-aware results, investors systematically overestimate their expected returns by 10-25%.

Gap 2: Options-Heavy, Factor-Light

India's backtesting ecosystem is dominated by options and technical analysis tools. Popular Indian algo and options trading platforms are excellent for options strategies — but offer no support for factor-based equity investing (momentum, value, quality, low volatility). If you want to test "buy the 30 lowest-volatility large-cap stocks and rebalance annually," no mainstream Indian tool could do this before BacktestIndia.

Gap 3: Survivorship Bias

Most Indian stock screeners and backtesting tools use only currently-listed stocks. This excludes companies that went bankrupt, delisted, or were acquired at poor prices during the backtest period — creating an upward bias in results. BacktestIndia's dataset includes 500+ stocks that traded on NSE since December 2006, including those subsequently delisted, to minimize this distortion.

Core Features: What Makes BacktestIndia Different

1. Automatic Indian Tax Calculations (LTCG + STCG)

This is BacktestIndia's most important differentiator. Every backtest automatically calculates capital gains taxes per the Finance Act 2024:

• LTCG (Long-Term Capital Gains): 12.5% tax on gains above ₹1.25 lakh per year for stocks held more than 1 year
• STCG (Short-Term Capital Gains): 20% tax on gains from stocks held less than 1 year
• Individual holding period tracking: Every stock position is tracked individually to classify gains correctly
• Tax loss set-off: Short-term losses offset short-term gains; long-term losses offset long-term gains; excess losses carry forward
• ₹1.25 lakh exemption: Applied before computing LTCG liability each year

The result is two separate performance numbers: Gross CAGR (pure strategy alpha) and Net CAGR (actual take-home return). The difference reveals the true cost of implementing a strategy in India.

Why this matters: BacktestIndia's research shows that annual rebalancing delivers a 0.44% CAGR advantage through LTCG treatment compared to monthly rebalancing — purely from tax efficiency. Over 18 years, that compounds to 8% more terminal wealth. Without tax-aware backtesting, you cannot make this comparison. See our detailed LTCG vs STCG Tax Impact Analysis.

2. 18+ Years of NSE Data (Including Delisted Stocks)

The platform covers December 2006 through December 2025 — spanning multiple complete market cycles: the 2007-2008 bull run and crash, the 2010-2013 sideways market, the 2014-2017 Modi rally, the 2020 COVID crash and recovery, and the 2022-2023 global tightening cycle. The dataset includes 500+ stocks, with companies that delisted during this period still present in historical calculations. Data is sourced from EODHD Financial APIs.

3. Sequential Multi-Factor Filtering

Rather than picking stocks randomly or using a single criterion, BacktestIndia lets you apply factor filters using a sequential filtering methodology that processes criteria in ordered layers. For example: start with the top 500 stocks by market cap → filter down to the 200 with lowest volatility → select the 60 with highest momentum → pick the final 30 with highest ROE. Each step narrows the universe based on a different quality, creating portfolios that combine multiple desirable characteristics.

4. Z-Score Composite Scoring

As an alternative to sequential filtering, you can combine multiple factors into a single composite score using Z-score normalization. Each factor is standardized to the same scale, weighted by your chosen percentages (e.g., 40% momentum + 30% ROE + 30% inverse P/E) — with an optional scaled turnover anti-speculation filter — and stocks are ranked by their composite score. This approach ensures no single factor dominates simply because it has larger raw numbers.

5. Realistic Cost Modeling

Every backtest applies 0.11% transaction costs per trade (covering STT, exchange fees, SEBI charges, GST, and brokerage) plus 0.05% slippage per trade for market impact. A round-trip trade costs approximately 0.32% of the transaction value — intentionally conservative to avoid over-optimism.

6. No Coding Required

BacktestIndia is entirely point-and-click. Select parameters from dropdowns, adjust sliders, and run backtests. No Python, R, or Excel formulas needed. Free users run pre-built templates with one click. Premium users customize all 14+ parameters through the same visual interface.

How It Works: Step-by-Step Walkthrough

Time required: Under 5 minutes for your first backtest.

Step 1: Choose a Strategy Template (or Build Custom)

Visit backtestindia.streamlit.app and select from 5 pre-built templates. Each template comes pre-configured with academically-backed factor parameters. Free users can run any template; Premium users can modify all parameters.

• Low Volatility: 30 least volatile stocks from top 100 by market cap
• Momentum: 30 highest momentum stocks (12M return minus last month)
• Quality-Momentum: High ROE + low debt → top momentum within quality subset
• Multi-Factor Blend: Z-score composite of momentum + quality + value
• Value-Quality: Low P/E + Low P/B combined with high ROE

Step 2: Set Parameters

Configure your backtest date range (Dec 2006–Dec 2025), initial capital (default ₹50 lakhs), rebalancing frequency (annual recommended for tax efficiency), and market cap universe (Top 100, 200, or 500 stocks). Premium users additionally set the number of stocks to hold, weighting scheme, and custom factor combinations.

Step 3: Run and Analyze Results

Click "Run Backtest." The engine processes every rebalance event — buying, selling, tracking holding periods, applying transaction costs, slippage, and LTCG/STCG taxes. Results appear in seconds, showing:

• Performance Dashboard: Gross CAGR, Net CAGR, total wealth created, benchmark comparison
• Equity Curve: Visual growth chart with strategy vs Nifty 50 overlay
• Risk Metrics: Annual volatility, maximum drawdown, recovery time, Sharpe ratio, Sortino ratio, Calmar ratio
• Drawdown Chart: Peak-to-trough decline visualization across all market crises
• Rolling Returns: Consistency analysis across different entry points
• Tax Breakdown: Total LTCG and STCG paid, effective tax drag on CAGR
• Transaction Log: Every buy, sell, and rebalance with costs applied

Step 4: Iterate

Modify parameters and re-run. Test different rebalancing frequencies to compare tax impact. Change the market cap universe. Add or remove factor filters. Each iteration takes seconds, allowing rapid comparison of strategy variations.

Factor Filters: 9 Academically-Backed Strategies You Can Test

BacktestIndia implements 9 factor filters, each grounded in decades of peer-reviewed academic research. These can be used individually, sequentially, or combined via Z-score composites.

How sequential filtering works in practice: Say you want a "Quality-Momentum" portfolio. You start with the top 200 stocks by market cap, filter down to the 60 with the highest ROE (quality screen), then select the 30 with the highest momentum from that quality subset. The result is a portfolio of 30 stocks that are both high-quality businesses and showing price momentum — systematically avoiding speculative, low-quality momentum plays.

The Tax Engine: How Automatic LTCG/STCG Calculation Works

This section explains the mechanics of BacktestIndia's tax calculation system — the feature that makes it unique among Indian backtesting tools.

How Taxes Are Applied in Each Backtest

At every rebalance date, the engine follows this sequence:

1. Identify exits: Stocks no longer qualifying for the portfolio are sold
2. Calculate holding period: Each exited stock's purchase date is compared to the sale date
3. Classify gains: Held over 1 year → LTCG (12.5% tax, ₹1.25L exemption). Held under 1 year → STCG (20% tax, no exemption)
4. Apply loss set-off: Short-term losses offset short-term gains first; long-term losses offset long-term gains first; excess losses carry forward
5. Annual tax payment: In December each year, total tax liability is deducted from portfolio cash balance

The tax efficiency insight: Because annual rebalancing means all stocks are held for 12+ months, virtually all gains qualify for the lower LTCG rate (12.5% vs 20%) and benefit from the ₹1.25L annual exemption. This structural advantage — documented across 5 strategy backtests — saves approximately 0.44% CAGR per year compared to monthly rebalancing.

Comparison: BacktestIndia vs Other Indian Backtesting Tools

Direct Answer: BacktestIndia is the only Indian platform purpose-built for factor-based equity backtesting with tax-aware results. Other Indian tools focus on options trading and technical analysis. Global portfolio tools don't model Indian tax rules. Here's how they compare:

Key takeaway: If you want to test options strategies or intraday technical setups, dedicated algo and options trading platforms are better choices. If you want to test systematic equity factor strategies (buy-and-hold approaches like momentum, value, low volatility) with realistic Indian tax impact, BacktestIndia is the only tool that supports this.

Published Research Results: 5 Strategies Tested Over 18+ Years

BacktestIndia has published 12 research articles — see all published factor investing backtests — testing 5 factor strategies over 18+ years of NSE data. All results include LTCG/STCG tax calculations, transaction costs, and slippage — including crisis performance across India's five major market downturns. Here's a summary of the key findings:

Key research finding: Annual rebalancing outperforms monthly rebalancing by approximately 0.44% CAGR per year across all 5 strategies — attributable purely to the tax efficiency of holding stocks for 12+ months (LTCG at 12.5% vs STCG at 20%). This finding is detailed in our LTCG vs STCG Tax Impact Analysis.

Additional research: Our Lost Decade analysis tested the Low Volatility strategy across 102 rolling 10-year entry points — it beat Nifty 50 in 100% of periods. Our Momentum Liquidity Premium study showed that all momentum alpha lives in low-turnover (illiquid) stocks — high-turnover momentum stocks actually underperformed Nifty 50.

Pricing: Free Tier vs Premium

Is the free tier enough? If you want to understand how factor investing strategies performed historically in India with tax-aware results, the free tier with 5 pre-built templates provides complete analysis including equity curves, drawdown analysis, rolling returns, and Nifty 50 comparison. Premium is for users who want to build custom multi-factor strategies, test different weightings, or experiment with factor combinations.

Frequently Asked Questions

About BacktestIndia

Platform: BacktestIndia.com
Launch App: backtestindia.streamlit.app
Data: EODHD Financial APIs (December 2006 – December 2025)
Coverage: 500+ NSE-listed stocks including delisted companies
Tax Compliance: Finance Act 2024 (LTCG 12.5%, STCG 20%)
SEBI Status: Educational tool, exempt under IA Regulations 2013, Reg. 3(1)(d)
Copyright: © 2025 T. Desai. Government of India Copyright Certificate No. SW-2025021891
Contact: backtestindia@gmail.com