Marshall Wace Q1 2026: $17.17B IVV Anchor

Marshall Wace's Q1 2026 13F is not a simple mega-cap chase. The London active quant manager reported $100.41B across 6,623 line items for the quarter ended 2026-03-31, and the single biggest line was still iShares Core S&P 500 ETF (IVV) at $17.17B. That is the hook: a systematic long-short manager can look diversified on the surface while one ETF sleeve defines the risk budget readers will notice first.

The SEC source is specific: Form 13F-HR filed 2026-05-15, accession 0001318757-26-000005. Marshall Wace's own description emphasizes quantitative, systematic and fundamental strategies, predominantly in long/short equity, while a Hedgeweek report citing Bloomberg said the firm planned to return roughly $3.1B to investors and reduce firm-wide assets to around $75B. That external backdrop makes the Q1 filing useful: the 13F book shows where U.S. listed exposure remained large after a capacity-discipline narrative entered the market.

TL;DR: the Q1 2026 Marshall Wace read

• Reported 13F value: $100.41B, down -8.6% from $109.85B in the prior platform snapshot.
• Risk anchor: IVV was $17.17B, or 17.10% of the Q1 13F value.
• Second ETF sleeve: SPDR Portfolio S&P 500 ETF was $3.80B, making index beta a visible part of the top stack.
• Single-name leaders: NVIDIA, Apple, Amazon and Microsoft followed the ETF layer.
• Interpretation: treat Marshall Wace as an active quant manager, not a passive index filer; the ETF exposure is portfolio construction, not the firm's identity.

What did Marshall Wace buy in Q1 2026?

The largest reported exposure was not a single operating company. IVV carried $17.17B, ahead of a $3.80B SPDR Portfolio S&P 500 ETF line and $2.38B in NVIDIA. The top of the book therefore reads like a two-layer construction: liquid market beta first, then high-liquidity mega-cap technology and growth exposure underneath.

The distinction matters for readers using 13F data as a signal. Marshall Wace is not Vanguard or BlackRock Fund Advisors. It is an active quant and long-short manager, so the ETF sleeve is better read as a portfolio implementation choice alongside security selection. The same top table also shows Apple at $2.13B, Amazon at $1.84B, and Microsoft at $1.25B, giving the book a clear large-cap U.S. growth core even before the broader tail is considered.

How concentrated was Marshall Wace's 2026Q1 13F?

The top-10 stack accounted for 31.76% of reported 13F value, with 68.24% left in the diversified tail. That is a different profile from a classic concentrated stock-picker. The hook is not that Marshall Wace put the whole book into one company; it is that the first slice of a very broad systematic book was dominated by a market ETF.

Beyond the ETF layer, the top-10 includes Alphabet Class A, Chevron, Tesla and Advanced Micro Devices. That mix helps explain why a casual list of top holdings can mislead: it compresses index exposure, AI semiconductor exposure, platform-company exposure and energy exposure into one ranking. The better question is whether the manager's largest liquid sleeves are balancing factor exposure rather than expressing a single-company thesis.

Why the AUM line is the real signal

Marshall Wace's reported 13F value stepped down from $109.85B to $100.41B, a -8.6% move. In isolation, that can look like a simple reduction. In context, it follows several quarters of expansion in the platform history, including $88.78B, $98.60B and $109.85B across the three prior snapshots.

The external capacity narrative reinforces that interpretation. A manager returning capital is usually trying to preserve opportunity quality, liquidity and execution flexibility. The Q1 13F does not prove why any one line moved, but it does show that Marshall Wace still had a $100.41B U.S.-listed footprint after the prior buildout. For readers comparing this filing with Qube Research's Q1 2026 quant rotation, the common lesson is that quant giants can change the risk wrapper without disappearing from the most liquid U.S. equities.

Which stocks mattered beyond IVV?

Single-name exposure still matters. NVIDIA at $2.38B remained the largest individual company line in the top group, while Apple at $2.13B and Amazon at $1.84B kept the book tied to mega-cap platform earnings. Broadcom and Taiwan Semiconductor ADR sat just below the top 10, adding more semiconductor exposure beyond NVIDIA and AMD.

The financial and defensive names are also worth noting. Morgan Stanley, Johnson & Johnson and Eli Lilly appear in the top-20 list, while Meta Platforms, Circle Internet Group and MercadoLibre show how the tail still reaches into high-beta internet, crypto infrastructure and Latin American e-commerce themes.

Analyst view: what a casual 13F summary misses

The casual takeaway is "Marshall Wace owns a lot of IVV." The better interpretation is that the Q1 2026 filing exposes the scaffolding of a large active quant platform: ETF beta at the top, liquid mega-cap equities underneath, and a very large residual tail. That is exactly why tracking Marshall Wace's full portfolio matters more than reading the first line in isolation.

For retail investors, the practical use is not to copy the ETF line. It is to watch the next quarter for whether the ETF anchor shrinks, whether NVIDIA and the semiconductor sleeve regain weight, and whether the diversified tail keeps absorbing the book. Those changes will say more about risk appetite than any single headline holding.

FAQ

What did Marshall Wace buy in Q1 2026?

Marshall Wace's largest Q1 2026 reported exposure was IVV at $17.17B, followed by SPDR Portfolio S&P 500 ETF at $3.80B and NVIDIA at $2.38B.

How much was Marshall Wace's 13F worth in 2026Q1?

Marshall Wace reported $100.41B in 13F value for 2026Q1, based on the SEC information table for accession 0001318757-26-000005.

Is Marshall Wace a passive index fund?

No. Marshall Wace is an active quant and long-short manager. Its ETF exposure should be read as portfolio construction inside an active platform, not passive index management.

What was Marshall Wace's biggest stock position in Q1 2026?

Excluding ETF exposure, NVIDIA was the largest individual company line in this article's top group at $2.38B, ahead of Apple at $2.13B and Amazon at $1.84B.