Data as of Sep 13, 2026. Both funds on the fields they both publish, from the same sources.
IWC vs SPY: how they differ
IWC and SPY hold 0% of their weight in the same names, and IWC returned more over the year.
iShares Micro-Cap ETF and SPDR S&P 500 ETF Trust.
What they hold in common
By the books each fund has filed, IWC and SPY hold 0% of their money in the same securities at the same weight.
| Only in IWC | Only in SPY |
|---|---|
| CAREDX 0.61% | NVIDIA CORP 8.08% |
| SELLAS LIFE SCIENCES GROUP INC 0.60% | APPLE INC 7.33% |
| NURIX THERAPEUTICS 0.59% | MICROSOFT CORP 5.59% |
| PENGUIN SOLUTIONS INC 0.58% | AMAZON.COM INC 3.77% |
| OUSTER 0.52% | ALPHABET INC CL A 2.98% |
| VIRIDIAN THERAPEUTICS ORS 0.48% | BROADCOM INC 2.61% |
| INTERFACE 0.47% | ALPHABET INC CL C 2.39% |
| MBX BIOSCIENCES 0.45% | META PLATFORMS INC CLASS A 2.16% |
Weight overlap is an ETFIQ calculation: for every security both funds hold, the smaller of the two weights, summed. Above 50%, holding both is close to holding one of them twice. Holdings dated Sep 10, 2026.
| IWC iShares Micro-Cap ETF | SPY SPDR S&P 500 ETF Trust | |
|---|---|---|
| Where it sits | Core index fund | Core index fund |
| Issuer | iShares | State Street |
| What it is | Russell Microcap | S&P 500 |
| Total return, 1 year | +31.3% | +17.5% |
| S&P 500 over the same days | +17.5% | +17.5% |
| Gap to the S&P 500 | +13.8 pts | 0.0 pts |
| Expense ratio | not published | 0.09% |
| Already in the S&P 500 | 91.9% | 100.0% |
| Holdings | 1252 | 505 |
IWC in plain words
IWC is an index equity fund tracking the Russell Microcap. Over the year to Sep 11, 2026 it returned +31.3% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. By its holdings filed for Sep 10, 2026, 92% of the fund by weight is stocks the S&P 500 also holds, across 1252 positions, with the top ten at 5.1%. It sat 5.0% below its high of Aug 14, 2026 on Sep 11, 2026.
SPY in plain words
SPY is an index equity fund tracking the S&P 500. Over the year to Sep 11, 2026 it returned +17.5% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.09% a year. By its holdings filed for Sep 10, 2026, 100% of the fund by weight is stocks the S&P 500 also holds, across 505 positions, with the top ten at 38.2%.
Questions people ask
- Which returned more over the last year, IWC or SPY?
- In the year to Sep 13, 2026, with distributions reinvested, IWC returned +31.3% and SPY returned +17.5%, so IWC returned more. One year is one year; the longer windows are in the table.
- How much do IWC and SPY overlap with the S&P 500?
- By their latest filed holdings, 92% of IWC and 100% of SPY by weight is stocks the S&P 500 already holds. Between the two funds, 0% of their books are the same securities at the same weight.
Other comparisons
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Where these figures came from
ETFIQ links to the documents behind every figure. It is not affiliated with any issuer, and a link is not an endorsement.
Cite this page. ETFIQ, IWC against SPY, data as of Sep 13, 2026. https://etfiq.com/compare/any/iwc-vs-spy Free to use with attribution; the underlying files are at Open data.
A comparison is not a recommendation. Standards and sources