SOXX vs SMH vs SOXQ: How Three Semiconductor ETFs Differ

SOXX, SMH and SOXQ are three US exchange-traded funds that hold baskets of chip stocks. Their names suggest one market, but each fund follows its own index, and each index has its own rules for which companies get in and how much any one company may weigh. Those rules decide how much of each fund is Nvidia, TSMC or SK hynix, and why the three do not move exactly together.

This explainer compares how the funds are built, using the sponsors’ prospectuses, holdings files and index rulebooks. Weights move every day; each figure below carries its date.

The three side by side

	SOXX	SMH	SOXQ
Sponsor	iShares (BlackRock)	VanEck	Invesco
Index	NYSE Semiconductor Index	MVIS US Listed Semiconductor 25 Index	PHLX Semiconductor Sector Index (SOX)
Index provider	ICE Data Indices	MarketVector Indexes (owned by VanEck)	Nasdaq
Companies	30	25	30
Largest weight allowed	8% per stock; 4% outside the five largest	20% per stock, with stocks above 4.5% capped at 50% together	12%, 10% and 8% for the three largest; 4% for the rest
ADR limit	All ADRs together at most 10%	None	None
Stated yearly expenses	0.33%	0.35%	0.19%
Net assets	US$43.2 billion (Oct 23, 2026)	US$66.6 billion (Oct 23, 2026)	US$2.4 billion (May 31, 2026)
Fund started	July 10, 2001	December 20, 2011	June 11, 2021

All three list on Nasdaq, and each prospectus classifies the fund as “non-diversified,” which means it may hold larger positions in fewer companies than a diversified fund. SOXQ’s assets come from its latest public holdings report to the SEC, dated May 31, 2026.

One name history matters. SOXX tracked the SOX until June 20, 2021; its prospectus says its benchmark “reflects the performance of the PHLX Semiconductor Sector Index through June 20, 2021 and the NYSE Semiconductor Index thereafter.” SOXQ, launched that month, is the fund that follows the SOX today.

How does each index pick its companies?

• NYSE Semiconductor Index (SOXX): the 30 largest US-listed companies in ICE’s semiconductors industry classification, ADRs included. The full list is rebuilt once a year in September, and weights are reset in March, June and December.
• MVIS US Listed Semiconductor 25 Index (SMH): 25 companies chosen from the 50 largest US-listed chip companies. A company needs at least 50% of its revenue from semiconductors to enter (25% to stay). The list is rebuilt in March and September, and weights are reset every quarter.
• SOX (SOXQ): the 30 largest US-listed companies in the semiconductors and chip-equipment subsectors of the Industry Classification Benchmark, ADRs included. An ADR counts only for the shares held at its US depositary bank. The list is rebuilt once a year in September, and weights are reset every quarter.

Where do the caps make the biggest difference?

The caps decide how far the largest companies can run ahead. SMH’s rules let one stock reach 20%; SOXX holds every stock to 8%. Between reset dates, weights drift with prices, so a stock can sit above its cap for a while.

The ten largest weights in each:

Rank	SOXX (Oct 22, 2026)	SMH (Oct 22, 2026)	SOX index (Sept 30, 2026)
1	AMD 9.22%	Nvidia 20.92%	Nvidia 11.35%
2	Nvidia 8.21%	TSMC 9.72%	Broadcom 8.67%
3	Intel 8.16%	Broadcom 5.56%	Micron 8.13%
4	Micron 7.63%	AMD 5.37%	Intel 4.91%
5	Broadcom 7.46%	Texas Instruments 5.29%	AMD 4.75%
6	Texas Instruments 4.58%	Micron 4.59%	Marvell 4.57%
7	Analog Devices 4.55%	Analog Devices 4.58%	Applied Materials 4.08%
8	Marvell 4.51%	ASML 4.48%	KLA 4.06%
9	Qualcomm 4.33%	Marvell 4.40%	TSMC 4.02%
10	KLA 3.60%	Qualcomm 4.06%	Analog Devices 4.01%

The SOXX and SMH columns come from each sponsor’s daily holdings file. The SOX column is the index’s own weighting from Nasdaq’s fact sheet; SOXQ’s holdings track it, before fees and cash.

Two results stand out. Nvidia is about a fifth of SMH but less than a tenth of SOXX. And SOXX’s 10% limit on all ADRs together keeps TSMC at 3.25% of the fund, against 9.72% in SMH, which has no such limit.

Where are the Asian chipmakers?

Company	SOXX (Oct 22)	SMH (Oct 22)	SOX (Oct 23 list)
TSMC (ADS, TSM)	3.25%	9.72%	Member (4.02% on Sept 30)
SK hynix (ADS, SKHY)	2.62%	3.66%	Not a member
ASML (Netherlands)	1.50%	4.48%	Member
Samsung Electronics	Not held	Not held	Not a member
Kioxia, Tokyo Electron, Advantest	Not held	Not held	Not members

SK hynix’s ADSs began trading on Nasdaq on July 10, 2026, and two of the three funds already hold them. The SOX asks for three months of trading before its yearly ranking date, the last trading day of July, and SK hynix’s ADSs had traded for three weeks by then, as our SOX explainer describes. Samsung Electronics has no US listing, and Kioxia trades in the US only over the counter (KXIAY), so neither can be in these indexes. Asia Chip Stocks From a US Account covers what each US ticker represents.

How far apart do they move?

Different weights mean different daily moves, even when the whole sector rises or falls together. Comparing SOXX’s Nasdaq closing prices with the SOX index’s closes over the 142 US sessions from April 2 to October 23, 2026:

Measure	Result
Change from April 1 to October 23	SOXX +41.41%, SOX +38.16%
Sessions that closed in the same direction	137 of 142
Average gap between the two daily moves	0.19 percentage points
Largest gap in one session	0.73 points (Aug 5: SOX −1.399%, SOXX −2.124%)

SOXX’s figures are fund prices, so they leave out dividends; the SOX here is its price index. Over this stretch the two moved together on almost every day, but the small daily gaps added up to about three points over six months. These numbers describe the past and say nothing about which way the gap runs next.

What else differs?

• Expenses. At the stated rates, a year’s expenses on US$10,000 come to about US$33 for SOXX, US$35 for SMH and US$19 for SOXQ.
• Size. By the net assets in the table, SMH and SOXX are many times larger than SOXQ.
• A split in November. iShares’ prospectus supplement says SOXX will split three-for-one: holders on record November 3, 2026 receive the new shares after the close on November 4, and SOXX trades at the split price from November 5. A price chart that is not adjusted will show a two-thirds drop on that day that is not a loss.

What do the index names in market reports mean?

“The SOX” in a market report is Nasdaq’s index, the one SOXQ follows; SOXX and SMH follow different baskets. For how the US indexes themselves are built, see Dow, S&P 500 and Nasdaq: What Each US Stock Index Measures.