S&P BYMA General: What It Measures and How It Is Built

Direct Answer

The S&P BYMA General is a rule-based measurement of broad market index of companies listed on Bolsas y Mercados Argentinos, maintained by S&P Dow Jones Indices/BYMA. 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 S&P BYMA General covers broad market index of companies listed on Bolsas y Mercados Argentinos, within the Argentina market. S&P Dow Jones Indices/BYMA 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

Constituents are weighted by float-adjusted market capitalization.

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

Stocks trading on BYMA that are classified as domestic, with an investable weight factor of at least 5% and a 12-month median daily value traded above ARS 100,000 (ARS 50,000 for current constituents). Each company is represented once by its designated listing, and every stock that passes the screens is included.

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

Stocks must have traded in at least 20% of trading sessions over the 12 months before the reference date. IPOs need at least three months of trading history and are added quarterly.

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

Rebalanced annually after the close on the third Friday of March, with the reference date on the third Friday of February. Share counts and weights are updated quarterly after the close on the third Friday of June, September and December. IPO additions use a reference date five weeks before the effective date.

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

A stock only has to have traded in 20% of sessions over 12 months. The S&P MERVAL is then selected from this index's constituents using additional size and liquidity screens.

References

• S&P Dow Jones Indices/BYMA: S&P Dow Jones Indices S&P/BYMA Indices Metodología (Spanish edition), as published 2023. Every rule described on this page is taken from this document.

Current S&P BYMA General constituents

S&P Dow Jones Indices/BYMA publishes and licenses the S&P BYMA General constituent list. Swoopr does not republish it here. The provider's own page is the authoritative source for current membership and weights.

S&P Dow Jones Indices/BYMA: official S&P BYMA General page

Related reading

• All stock market indexes: how indexes are built, weighted and revised.
• Emerging Markets indexes: others covering the same region.
• Index concentration: measuring how much of an index sits in its largest holdings.
• Index rebalancing and inclusion effects: what happens to a stock when index membership changes.

Frequently Asked Questions