BESS

The theme line is green when its cumulative rebased performance is above Nifty 500 and red when it is below. The chart callout shows the latest relative performance as the theme level divided by the benchmark level, minus one.

The basket uses the theme's current reviewed companies. For each available week, we calculate every valid constituent's close-to-close return and give each company the same weight. If a weekly rollup is missing or lags the daily series, the final available daily close in that week is used.

For baskets with at least 10 valid stocks, the highest and lowest 5% of weekly returns are trimmed to reduce split, corporate-action, and single-stock distortions. Weekly basket returns are then compounded and rebased to 100 beside the Nifty 500.

Breadth is the share of valid constituents that rose that week. Coverage is the number with usable aligned prices divided by current membership. Weekly moves above 80% are excluded as likely data or corporate-action outliers.

Limitation: this is a current-membership historical reconstruction, not a point-in-time investable index. It can contain survivorship bias and excludes costs, liquidity impact, dividends, and rebalancing turnover.

Model note: Current-member weekly equal-weight returns (5% tails trimmed for baskets of 10+), compounded and rebased to 100 against Nifty 500; lagging weekly rollups are patched with the final available daily close, and rotation uses 13-week excess return with four-week acceleration.