--- title: "WIG: Methodology" description: "WIG is maintained by GPW Benchmark and covers broad Polish equity benchmark. How the index selects and weights its constituents, and what it measures." canonical: https://www.getswoopr.com/stocks/indexes/wig/ source: "Swoopr Investment: https://www.getswoopr.com" --- # WIG: What It Measures and How It Is Built ## Direct Answer > The WIG is a rule-based measurement of broad Polish equity benchmark, maintained by GPW Benchmark. Like every index it owns nothing: it is a number produced by applying a published weighting formula to a selected list of companies, revised on a schedule the provider sets. ## What this index covers The WIG covers broad Polish equity benchmark, within the Poland market. GPW Benchmark defines which securities are eligible, how they are selected from that pool, and how much each one contributes to the published number. The index name does not state a fixed company count, so the number of constituents follows the eligibility rules rather than a target. ## How constituents are weighted Weighted by free float shares times price. A single company may not exceed 10% of the index and companies from one exchange sector may not exceed 30%, with reductions applied above those limits. WIG is a total return index, so it includes dividends and subscription rights. The weighting method is the single biggest driver of how an index behaves. Two indexes covering the same market can diverge for years purely because they weight differently, which is why comparing index levels without knowing the method tells you very little. ## What qualifies for inclusion All GPW Main List companies that meet the base criteria. Base criteria for every GPW exchange index: free float above 10%, free float value above 1 million euros, at least one trade in the last three months, no special marking such as bankruptcy, and no alert list or lower liquidity segment. A dual listed company is excluded when its parent market volume over three months is more than 20% above its GPW volume and its average price on the two markets differs by more than 20%. Eligibility rules are the part of an index most readers never look at and the part that decides what it can possibly measure. A screen that excludes a whole sector, or admits only one listing venue, shapes the result far more than any day of trading does. ## How long a listing must exist first A company that has an IPO is verified seven days after it, with the free float share count assessed after five sessions, and enters between reviews if it meets all the requirements for periodic modifications. A seasoning rule is why a large new listing does not appear in an index the week it starts trading. It is a deliberate lag, and it means an index can under-represent a fast-growing part of the market for months at a time. ## When the membership is revised Participants are selected on data after the last session of February, May, August and November. Changes take effect after the session on the third Friday of March, June, September and December, announced one week ahead. Reconstitution is the one date an index changes shape by design rather than by price. Funds tracking it have to trade toward the new membership, which is why the schedule matters to anyone holding the tracker rather than only to the provider. ## The rule that surprises people WIG is a total return index with dividends included, while WIG20, mWIG40, sWIG80 and WIG30 are price indices. WIG carries an exchange sector cap of 30%, while WIG20 and WIG30 instead limit the number of companies per sector. ## References - [GPW Benchmark: GPW Benchmark, GPW Benchmark Indices, March 2026 edition (index profiles, calculation principles and periodic modifications)](https://www.gpwbenchmark.pl/pub/BENCHMARK/files/PDF/opis_indeksow/IndicesGPWB_0326.pdf), as published 2026. Every rule described on this page is taken from this document. ## Current WIG constituents GPW Benchmark publishes and licenses the WIG constituent list. Swoopr does not republish it here. The provider's own page is the authoritative source for current membership and weights. [GPW Benchmark: official WIG page](https://gpwbenchmark.pl/en-home) ## Related reading - [All stock market indexes](https://www.getswoopr.com/stocks/indexes/): how indexes are built, weighted and revised. - [Europe indexes](https://www.getswoopr.com/stocks/indexes/europe/): others covering the same region. - [Index concentration](https://www.getswoopr.com/technical-analysis/market-concentration/index-concentration/): measuring how much of an index sits in its largest holdings. - [Index rebalancing and inclusion effects](https://www.getswoopr.com/stocks/corporate-actions-catalysts/index-rebalancing-and-inclusion-effects/): what happens to a stock when index membership changes. ## Frequently Asked Questions ### Who maintains the WIG? GPW Benchmark maintains the WIG and publishes the methodology document that defines its eligibility and weighting rules. ### What does the WIG measure? It measures broad Polish equity benchmark. The index is a calculated number applying a weighting formula to a selected list of companies, and it holds nothing itself. ### Where can I see the current WIG constituents? GPW Benchmark publishes the current constituent list. Swoopr does not republish it, because index providers license constituent data and Swoopr holds no such licence. ## About the author The [Swoopr Editorial Team](https://www.getswoopr.com/authors/swoopr-editorial-team/) writes Swoopr Investment's educational library, covering market structure, analysis methods and the mechanics behind the numbers investors read every day. Our [editorial policy](https://www.getswoopr.com/legal/editorial-policy/) and [corrections policy](https://www.getswoopr.com/legal/corrections-policy/) set out how this content is produced, reviewed and fixed when it is wrong.