Direct Answer
The ASCX (AEX Small-Cap Index) covers Dutch small-cap companies listed on Euronext Amsterdam that rank below the AMX tier in free-float-adjusted market capitalisation. Administered by Euronext, it is the third tier of the Dutch AEX family, providing a benchmark for the smaller end of the Netherlands listed equity market.
What this index covers
The ASCX (AEX Small-Cap Index) covers the Netherlands equity market through the Euronext Amsterdam. Euronext defines which securities are eligible, how they are selected from that pool and how much each contributes to the published number.
The eligible universe is: Dutch small-cap equities listed on Euronext Amsterdam that meet minimum eligibility criteria and rank below the AMX universe by free-float-adjusted market capitalisation, per the Euronext published methodology.
Understanding the eligible universe is the most important step in understanding what an index measures. An index that selects by listing venue will behave differently from one that selects by company domicile, and a sector index will have very different risk characteristics from a broad market measure even if they share some constituents.
How constituents are weighted
Free-float-adjusted market-capitalisation weighting, per the Euronext published methodology.
Weighting is the mechanism that translates a list of companies into a single number. Free-float-adjusted market-capitalisation weighting is the most common method: larger companies contribute more to the index level than smaller ones, and the free-float adjustment excludes shares that are not available to public investors (such as government-held strategic stakes or closely-held founder shares). This makes the index level reflect the actual investable market rather than total market size.
Eligible universe and eligibility rules
Eligibility rules determine which companies can be included at a review and which must exit. The key dimensions to verify are: which exchange or market segment is in scope; whether domicile or listing venue determines eligibility; the minimum free-float threshold; the liquidity screen; and whether there are sector restrictions.
For the ASCX (AEX Small-Cap Index), the relevant market is the Euronext Amsterdam and the administrator is Euronext. Per the published Euronext methodology (verification date: August 31, 2026), the eligible universe is defined as: Dutch small-cap equities listed on Euronext Amsterdam that meet minimum eligibility criteria and rank below the AMX universe by free-float-adjusted market capitalisation, per the Euronext published methodology.
Reconstitution schedule
Quarterly, aligned with the AEX family review schedule.
Reconstitution is the date on which the index changes shape by design rather than by price. Passive funds tracking the index must trade toward the new membership list, which creates predictable order flow around the review date. Active managers often position around reconstitution events to capture or avoid that flow.
How investors use this index
Dutch small-cap benchmark; reference for mandates seeking exposure to smaller Dutch listed companies; supports size-factor analysis within the Netherlands equity market.
For any index, three uses are distinct: as a performance benchmark (measuring how well a portfolio did relative to the market), as a product underlying (an ETF or structured product replicating the index), and as a research reference (tracking market-cap, sector weights or concentration over time). The same index can serve all three purposes, but the choice of which to use depends on the investment mandate and the specific question being answered.
Comparisons with related indexes
The ASCX (AEX Small-Cap Index) is most often compared with:
- AMX: Dutch mid-cap index one size tier above the ASCX.
- AEX: Dutch large-cap flagship; the ASCX is the small-cap complement at the other end of the size spectrum.
- AEX All-Share: covers all qualifying Dutch listings including large, mid and small; ASCX is the small-cap slice.
When switching from one benchmark to another, the practical question is what changes in coverage: does the alternative add smaller companies, exclude a sector, change the weighting method or extend to a different currency? Each of these changes alters what the index can tell you about market performance.
References
- Euronext: Index Products, as published per the provider's methodology page. All methodology claims on this page are derived from this source.
Current ASCX (AEX Small-Cap Index) constituents
Euronext publishes and licenses the ASCX (AEX Small-Cap Index) constituent list. Swoopr does not republish it here. The provider's own page is the authoritative source for current membership and weights.
Related reading
- All stock market indexes: how indexes are built, weighted and revised.
- European Stock Market 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
Who administers the ASCX?
Euronext administers the ASCX under its published index methodology.
What does ASCX stand for?
ASCX stands for AEX Small-Cap Index. It is the small-cap tier of the Dutch AEX index family.
How is the ASCX positioned relative to the AEX and AMX?
The AEX covers the 25 largest Dutch companies; the AMX covers the next 25 mid-caps; the ASCX covers the qualifying smaller companies below the AMX threshold.
How often is the ASCX reconstituted?
Quarterly, on the same schedule as the AEX and AMX.
Where can I find current ASCX data?
Euronext publishes index data on its official pages. Swoopr does not republish licensed constituent lists.