The European ETF market is concentrated in a handful of issuers. Knowing who runs which product matters because each issuer publishes holdings on their own site, in their own format, behind their own URL pattern. The list below covers roughly 80% of European UCITS AUM — get adapters for these eight and you can resolve almost any ETF you'll encounter in the wild.
Top 8 issuers · typical sizes per ETF
IssuerFormatSize / ETFRows
iShares / BlackRockCSV50–500 KB30–3,000
Xtrackers (DWS)CSV20–300 KB30–2,000
VanguardJSON30–400 KB50–4,000
SPDR (SSGA)XLSX100–800 KB50–3,000
InvescoCSV20–200 KB30–1,500
AmundiXLSX50–400 KB30–2,000
VanEckCSV10–100 KB20–500
WisdomTreeCSV20–200 KB30–1,500
Who's who
iShares / BlackRock
The largest ETF issuer in the world and the dominant force in European UCITS; per-product CSVs are served from product pages keyed by an internal numeric ID (e.g., 319084), not the ISIN.
Xtrackers (DWS)
Deutsche Bank's ETF arm, strong in core European equity and fixed-income indices; holdings download as a clean CSV keyed by ISIN.
Vanguard
Famous for ultra-low TER index funds; the European site exposes holdings via an internal JSON endpoint rather than a downloadable CSV, which is the easiest to parse once discovered.
SPDR (SSGA)
State Street Global Advisors, the issuer of the original SPY; European UCITS holdings ship as XLSX with consistent column headers across the catalog.
Invesco
Mid-sized issuer with a heavy focus on smart-beta and thematic ETFs; CSV files are small and trivial to parse.
Amundi
Europe's largest asset manager (post-Lyxor merger); holdings come as XLSX and the per-country sites occasionally re-localize column names.
VanEck
Specialist in tightly-scoped thematic ETFs (semis, defense, miners); files are compact because most products track narrow universes.
WisdomTree
Known for fundamentally-weighted and thematic strategies; CSV downloads are uniform across the catalog, which makes a single adapter cover the whole lineup.
Outliers worth knowing
- Broad-market ETFs (e.g., iShares MSCI ACWI ~9,000 holdings) hit ~1.5 MB CSV.
- Single-country / sector ETFs (like SEC0, ~80 holdings) are under 50 KB.
- Bond ETFs are the chunkiest — iShares AGG-equivalents can have 10,000+ line items, 2–3 MB.
Weekly ingestion math
Say you track 500 ETFs, avg 300 KB each:
- ~150 MB per refresh. Trivial.
- At ~1 req/sec (polite rate to avoid getting blocked): ~8 minutes total wall time.
- Parsed + normalized into a DB: maybe 2–5M rows total. Postgres handles this without thinking.
Further reading
Europe
https://www.justetf.com/en/how-to/justETF's "how-to" hub is the most pragmatic external reference on the European ETF landscape — issuer profiles, strategy guides, and screening walk-throughs.
United States
https://www.etf.com/etf-education-centerETF.com's education center is the US counterpart — screener, issuer pages, and tutorials covering the much larger and more liquid American ETF universe.