--- title: "ETFs net sold $31.3 million of FormFactor on its first day in the S&P MidCap 400" description: "FormFactor's S&P MidCap 400 debut on October 6 came with $367.9 million of ETF buying that had already printed before the effective date, then net selling of $31.3 million on the day itself, led by funds tied to the SmallCap 600 list the stock had just left. The shares closed their first session in the index down 4.5 percent and now sit below the analyst consensus they cleared." publisher: "The Inference" section: "Money" published: 2026-10-09T13:20:18.708Z modified: 2026-10-09T13:20:18.708Z canonical: https://theinference.org/article/etfs-net-sold-31-3-million-of-formfactor-on-its-first-day-in-the-s-p-midcap-400 language: en keywords: "ETFs, Index Funds, S&P MidCap 400, FormFactor, Semiconductors" --- # ETFs net sold $31.3 million of FormFactor on its first day in the S&P MidCap 400 > FormFactor's S&P MidCap 400 debut on October 6 came with $367.9 million of ETF buying that had already printed before the effective date, then net selling of $31.3 million on the day itself, led by funds tied to the SmallCap 600 list the stock had just left. The shares closed their first session in the index down 4.5 percent and now sit below the analyst consensus they cleared. ## The buying the rule promised never printed on the day [FormFactor's first session in the S&P MidCap 400](https://theinference.org/markets/companies/formfactor) was Tuesday, October 6, the morning funds tied to the index were obliged to add the stock [1]. [The ETF record shows them finishing the day as net sellers](https://www.gurufocus.com/news/9114951/etfs-are-net-sellers-of-formfactor-form-on-tuesday), $31.3 million out, nineteen funds buying against six selling in larger size, and no MidCap 400 tracker anywhere among the named trades [2]. The stock fell 4.5 percent to $141.30 [3]. The inclusion trade, the one priced into every index promotion, never showed up on the day it was scheduled for. ## The biggest sellers were leaving the old list XSMO sold its entire holding, 722,471 shares, for $102.1 million [2]. It is Invesco's S&P SmallCap Momentum ETF, a $2.91 billion fund whose momentum basket is culled from the S&P SmallCap 600 [4]. The number two seller, VIOG at $13.7 million, is Vanguard's S&P Small-Cap 600 Growth fund, built by full replication to hold every stock in its index [5]. The same S&P notice that promoted FormFactor to the MidCap 400 deleted it from the SmallCap 600, with Workiva taking the old seat [1]. The third seller, RWJ at $1.4 million, is Invesco's S&P SmallCap 600 Revenue ETF, which re-weights the entire 600 list by revenue [6]. On this record, the deletion likely pushed more money out of the 600's funds than the addition funneled through the 400's: the three largest sellers all track 600-derived lists, and their combined $117.2 million of sell-outs tops the whole day's $31.3 million net swing [2][4][5][6]. *Chart: **Every big seller on the day ran a list FormFactor had just been deleted from** Column chart of the largest ETF net sellers of FormFactor on October 6, 2026, all three tracking S&P SmallCap 600 derived lists.* *Net ETF sales of FormFactor stock on October 6, 2026, millions of dollars. The three largest sellers all track lists derived from the S&P SmallCap 600, the index FormFactor left the same day. Source: GuruFocus ETF holdings-change data, published October 8, 2026; fund profiles at etf.com, Vanguard and Invesco. [2][4][5][6]* ## The front-run crowd paid 102 times earnings The buying did arrive, before the effective date: $68.9 million net on October 2 and $299.0 million on October 5, $367.9 million combined [2]. [That tape ran the stock to $149.31 on September 30 and $148.44 on October 1](https://seekingalpha.com/news/4648777-formfactor-advances-10-amid-extended-rally), [102.3 times trailing earnings](https://sagenoodle.com/research/formfactor-stock-q2-growth-meets-a-102-times-earnings-price) against a five-year median of 42.4 [7][1]. By the October 8 close it sat at $137.13, below the $145.44 average of eleven analyst targets it had cleared to get in [7][1]. Inclusion is not a vote of confidence; it is a change of address, and the moving costs land on whoever bought the announcement. *Chart: **The inclusion buying front-ran the effective date, then reversed on the day** Column chart of net ETF flow into FormFactor around its S&P MidCap 400 inclusion, showing heavy buying on October 2 and 5 and net selling on the October 6 effective date.* *Net ETF purchases of FormFactor stock, millions of dollars per trading day, around the October 6, 2026 S&P MidCap 400 effective date. Source: GuruFocus ETF holdings-change data, published October 8, 2026. [2]* ## October 28 prices the unnamed customer The bull case carries receipts: [record second-quarter revenue of $258.2 million, up 32 percent](https://theinference.org/article/s-p-promotes-formfactor-into-the-midcap-400-where-funds-must-buy-what-insiders-keep-selling), and a Deutsche Bank target of $200 built on a $500 million second-source opportunity at [Nvidia](https://theinference.org/markets/companies/nvidia) [1]. The company itself has named only "a newly qualified GPU program," never the customer [1]. Insiders, for their part, sold $22.1 million over twelve months without buying a share; chief executive Mike Slessor filed a sale in every month of 2026 through September [1]. The third quarter, guided to $270 million of revenue plus or minus $10 million, [reports on October 28](https://finance.yahoo.com/markets/stocks/articles/formfactor-announce-third-quarter-2026-200100508.html) [8][9]. That print decides whether the front-run crowd bought a business or a list. ## Takeaway FormFactor's index promotion produced its buying early and its selling on the day: $367.9 million of ETF inflows printed before the October 6 effective date, then $31.3 million net out, led by SmallCap 600 trackers deleting the stock. The shares closed the session down 4.5 percent and October 28's third-quarter print now decides whether the front-run crowd bought a business or a list. ## Sources 1. [The Inference, S&P Promotes FormFactor Into the MidCap 400, Where Funds Must Buy What Insiders Keep Selling, 2 October 2026](https://theinference.org/article/s-p-promotes-formfactor-into-the-midcap-400-where-funds-must-buy-what-insiders-keep-selling) 2. [GuruFocus, ETFs Are Net Sellers of FormFactor (FORM) on Tuesday, 8 October 2026](https://www.gurufocus.com/news/9114951/etfs-are-net-sellers-of-formfactor-form-on-tuesday) 3. [GuruFocus, FormFactor Inc (FORM) Shares Fall 4.5%: What GF Score of 77 Tells Investors, 6 October 2026](https://www.gurufocus.com/news/9112251/formfactor-inc-form-shares-fall-45-what-gf-score-of-77-tells-investors) 4. [etf.com, Invesco S&P SmallCap Momentum ETF (XSMO) fund profile, retrieved 9 October 2026](https://www.etf.com/XSMO) 5. [Vanguard, Vanguard S&P Small-Cap 600 Growth ETF (VIOG) fund profile, retrieved 9 October 2026](https://investor.vanguard.com/investment-products/etfs/profile/viog) 6. [Invesco, Invesco S&P SmallCap 600 Revenue ETF (RWJ) fund page, retrieved 9 October 2026](https://www.invesco.com/us/financial-products/etfs/product-detail?audienceType=Investor&ticker=RWJ) 7. [Seeking Alpha, FormFactor advances 10% amid extended rally, 30 September 2026, page carrying the 8 October 2026 close](https://seekingalpha.com/news/4648777-formfactor-advances-10-amid-extended-rally) 8. [SageNoodle, Is Formfactor (FORM) Stock Undervalued? Fair Value vs Price, 7 October 2026](https://sagenoodle.com/research/formfactor-stock-q2-growth-meets-a-102-times-earnings-price) 9. [FormFactor via GlobeNewswire on Yahoo Finance, FormFactor to Announce Third Quarter 2026 Financial Results on October 28th, 7 October 2026](https://finance.yahoo.com/markets/stocks/articles/formfactor-announce-third-quarter-2026-200100508.html) --- ETFs net sold $31.3 million of FormFactor on its first day in the S&P MidCap 400 — The Inference. Canonical: https://theinference.org/article/etfs-net-sold-31-3-million-of-formfactor-on-its-first-day-in-the-s-p-midcap-400