FormFactor, Inc.
US ˙ NasdaqGS ˙ US3463751087

SecurityFORM / FormFactor, Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership200,874 shares
Latest Disclosed Value $ 19,482,769
Citadel Advisors Llc ownership in FORM / FormFactor, Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 200,874 shares of FormFactor, Inc. (US:FORM) valued at $19,482,769 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 193,009 shares of FormFactor, Inc.. This represents a change in shares of 4.07% during the quarter. The current value of the position is $23,441,996 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (FORM) in the form of stock options. The firm currently holds call options representing 54,800 of underlying shares valued at $5,315,052 USD and put options representing 31,700 of underlying shares valued at $3,074,583 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

FORM / FormFactor, Inc. Historical Put/Call Ratio
Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date
Effective
Date
Form Security Class ID Avg Price
Paid (Est)
Reported
Shares
ΔShares ΔShares
(%)
Reported
Value
(x1000)
ΔValue
(%)
Alloc
(%)
ΔAlloc ΔAlloc (%) Cost Basis
(x1000)
Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F FORMFACTOR COM 346375108 200,874 7,865 4.07 19,483 80.96 0.0028
2026-02-17 2025-12-31 13F FORMFACTOR COM 346375108 193,009 87,099 82.24 10,766 179.13 0.0016
2025-11-14 2025-09-30 13F FORMFACTOR COM 346375108 105,910 51,616 95.07 3,857 106.48 0.0006
2025-08-14 2025-06-30 13F FORMFACTOR COM 346375108 54,294 54,294 1,868 0.0003
2025-05-15 2025-03-31 13F FORMFACTOR COM 346375108 0 -51,511 -100.00 0 -100.00
2025-02-14 2024-12-31 13F FORMFACTOR COM 346375108 51,511 31,166 153.19 2,266 142.35 0.0004
2024-11-14 2024-09-30 13F FORMFACTOR COM 346375108 20,345 20,345 936 0.0002
2024-05-15 2024-03-31 13F FORMFACTOR COM 346375108 0 -40,530 -100.00 0 -100.00
2024-02-14 2023-12-31 13F FORMFACTOR COM 346375108 40,530 -17,809 -30.53 1,691 -17.08 0.0003
2023-11-14 2023-09-30 13F FORMFACTOR COM 346375108 58,339 -367,098 -86.29 2,038 -86.00 0.0004
2023-08-14 2023-06-30 13F FORMFACTOR COM 346375108 425,437 -27,696 -6.11 14,558 0.87 0.0030
2023-05-15 2023-03-31 13F FORMFACTOR COM 346375108 453,133 199,679 78.78 14,432 156.16 0.0032
2023-02-14 2022-12-31 13F FORMFACTOR COM 346375108 253,454 65,720 35.01 5,634 19.82 0.0013
2022-11-14 2022-09-30 13F FORMFACTOR COM 346375108 187,734 165,599 748.13 4,702 448.66 0.0011
2022-08-15 2022-06-30 13F FORMFACTOR COM 346375108 22,135 22,135 857 0.0002
2022-05-16 2022-03-31 13F FORMFACTOR COM 346375108 0 -15,845 -100.00 0 -100.00
2022-02-14 2021-12-31 13F FORMFACTOR COM 346375108 15,845 -16,675 -51.28 724 -40.36 0.0001
2021-11-15 2021-09-30 13F FORMFACTOR Cmn 346375108 32,520 -125,647 -79.44 1,214 -78.95 0.0003
2021-08-16 2021-06-30 13F FORMFACTOR COM 346375108 158,167 87,553 123.99 5,767 81.07 0.0013
2021-05-21 2021-03-31 13F/A-1 FORMFACTOR COM 346375108 70,614 70,614 3,185 0.0008
2021-05-17 2021-03-31 13F FORMFACTOR COM 346375108 70,614 70,614 3,185 0.0008
2021-02-16 2020-12-31 13F FORMFACTOR COM 346375108 0 -88,241 -100.00 0 -100.00
2020-11-16 2020-09-30 13F FORMFACTOR COM 346375108 88,241 -178,414 -66.91 2,200 -71.87 0.0006
2020-08-14 2020-06-30 13F FORMFACTOR Cmn 346375108 266,655 213,930 405.75 7,821 638.53 0.0028
2020-05-15 2020-03-31 13F FORMFACTOR Cmn 346375108 52,725 -4,452 -7.79 1,059 18.19 0.0005
2019-08-14 2019-06-30 13F FORMFACTOR Cmn 346375108 57,177 45,554 391.93 896 379.14 0.0004
2019-05-15 2019-03-31 13F FORMFACTOR Cmn 346375108 11,623 11,623 187 0.0001
2018-11-13 2018-09-30 13F FORMFACTOR Cmn 346375108 0 -13,908 -100.00 0 -100.00
2018-08-14 2018-06-30 13F/A-1 FORMFACTOR Cmn 346375108 13,908 -81,590 -85.44 185 -85.81 0.0001
2018-08-10 2018-06-30 13F FORMFACTOR Cmn 346375108 13,908 -81,590 185
2018-05-14 2018-03-31 13F/A-1 FORMFACTOR Cmn 346375108 95,498 -440,133 -82.17 1,304 -84.44 0.0007
2018-05-11 2018-03-31 13F FORMFACTOR Cmn 346375108 95,498 -440,133 1,304
2018-02-09 2017-12-31 13F FORMFACTOR Cmn 346375108 535,631 518,568 3,039.14 8,382 2,810.42 0.0051
2017-11-09 2017-09-30 13F FORMFACTOR Cmn 346375108 17,063 -516 -2.94 288 32.11 0.0002
2017-08-11 2017-06-30 13F FORMFACTOR Cmn 346375108 17,579 -31,046 -63.85 218 -62.15 0.0002
2017-05-12 2017-03-31 13F FORMFACTOR Cmn 346375108 48,625 31,292 180.53 576 196.91 0.0005
2017-02-10 2016-12-31 13F FORMFACTOR Cmn 346375108 17,333 -162,013 -90.34 194 -90.03 0.0002
2017-01-31 2016-09-30 13F/A-1 FORMFACTOR Cmn 346375108 179,346 148,420 479.92 1,946 600.00 0.0020
2016-11-10 2016-09-30 13F FORMFACTOR INC CMN STK Cmn 346375108 179,346 1,946
2017-01-31 2016-06-30 13F/A-1 FORMFACTOR Cmn 346375108 30,926 30,926 0.00 278 0.0003
2016-08-12 2016-06-30 13F FORMFACTOR INC CMN STK Cmn 346375108 30,926 278
2017-01-31 2016-03-31 13F/A-1 FORMFACTOR INC CMN STK Cmn 346375108 0 -2,478 -100.00 0 -100.00
2017-01-31 2015-12-31 13F/A-1 FORMFACTOR Cmn 346375108 2,478 -9,257 -78.88 22 -72.50 0.0000
2016-02-12 2015-12-31 13F FORMFACTOR INC CMN STK Cmn 346375108 2,478 22
2015-11-16 2015-09-30 13F FORMFACTOR INC CMN STK Cmn 346375108 11,735 -59,266 -83.47 80 -87.75 0.0001
2015-08-14 2015-06-30 13F FORMFACTOR INC CMN STK Cmn 346375108 71,001 -176,879 -71.36 653 -70.29 0.0006
2015-05-15 2015-03-31 13F FORMFACTOR INC CMN STK Cmn 346375108 247,880 -34,208 -12.13 2,198 -9.44 0.0024
2015-02-17 2014-12-31 13F FORMFACTOR INC CMN STK Cmn 346375108 282,088 127,535 82.52 2,427 119.24 0.0029
2014-11-14 2014-09-30 13F FORMFACTOR INC CMN STK Cmn 346375108 154,553 89,316 136.91 1,107 103.87 0.0014
2014-08-14 2014-06-30 13F FORMFACTOR INC CMN STK Cmn 346375108 65,237 690 1.07 543 31.80 0.0007
2014-05-15 2014-03-31 13F FORMFACTOR INC CMN STK Cmn 346375108 64,547 48,821 310.45 412 333.68 0.0006
2014-02-14 2013-12-31 13F FORMFACTOR INC CMN STK Cmn 346375108 15,726 200 1.29 95 -11.21 0.0001
2013-11-14 2013-09-30 13F FORMFACTOR INC CMN STK Cmn 346375108 15,526 -15,146 -49.38 107 -48.31 0.0002
2013-08-14 2013-06-30 13F FORMFACTOR INC CMN STK Cmn 346375108 30,672 30,672 207 0.0004
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-15 2026-03-31 13F FORMFACTOR COM Call 54,800 14.17 5,315 98.54 n/a n/a n/a
2026-02-17 2025-12-31 13F FORMFACTOR COM Call 48,000 -50.46 2,677 -24.14 n/a n/a n/a
2025-11-14 2025-09-30 13F FORMFACTOR COM Call 96,900 30.07 3,529 37.69 n/a n/a n/a
2025-08-14 2025-06-30 13F FORMFACTOR COM Call 74,500 -10.67 2,564 8.65 n/a n/a n/a
2025-05-15 2025-03-31 13F FORMFACTOR COM Call 83,400 35.61 2,359 -12.82 n/a n/a n/a
2025-02-14 2024-12-31 13F FORMFACTOR COM Call 61,500 34.87 2,706 29.04 n/a n/a n/a
2024-11-14 2024-09-30 13F FORMFACTOR COM Call 45,600 36.94 2,098 4.07 n/a n/a n/a
2024-08-14 2024-06-30 13F FORMFACTOR COM Call 33,300 39.33 2,016 84.86 n/a n/a n/a
2024-05-15 2024-03-31 13F FORMFACTOR COM Call 23,900 181.18 1,091 207.91 n/a n/a n/a
2024-02-14 2023-12-31 13F FORMFACTOR COM Call 8,500 -47.20 355 -37.01 n/a n/a n/a
2023-11-14 2023-09-30 13F FORMFACTOR COM Call 16,100 19.26 563 21.91 n/a n/a n/a
2023-08-14 2023-06-30 13F FORMFACTOR COM Call 13,500 14.41 462 22.93 n/a n/a n/a
2023-05-15 2023-03-31 13F FORMFACTOR COM Call 11,800 2.61 376 47.06 n/a n/a n/a
2023-02-14 2022-12-31 13F FORMFACTOR COM Call 11,500 -29.88 256 -37.96 n/a n/a n/a
2022-11-14 2022-09-30 13F FORMFACTOR COM Call 16,400 84.27 411 19.13 n/a n/a n/a
2022-08-15 2022-06-30 13F FORMFACTOR COM Call 8,900 -36.43 345 -41.33 n/a n/a n/a
2022-05-16 2022-03-31 13F FORMFACTOR COM Call 14,000 -15.15 588 -22.02 n/a n/a n/a
2022-02-14 2021-12-31 13F FORMFACTOR COM Call 16,500 -57.25 754 -47.68 n/a n/a n/a
2021-11-15 2021-09-30 13F FORMFACTOR Cmn Call 38,600 -2.77 1,441 -0.41 n/a n/a n/a
2021-08-16 2021-06-30 13F FORMFACTOR COM Call 39,700 23.29 1,447 -0.41 n/a n/a n/a
2021-05-21 2021-03-31 13F/A FORMFACTOR COM Call 32,200 -55.03 1,453 -52.82 n/a n/a n/a
2021-05-17 2021-03-31 13F FORMFACTOR COM Call 32,200 1,453 n/a n/a n/a
2021-02-16 2020-12-31 13F FORMFACTOR COM Call 71,600 113.10 3,080 267.54 n/a n/a n/a
2020-11-16 2020-09-30 13F FORMFACTOR COM Call 33,600 57.01 838 33.44 n/a n/a n/a
2020-08-14 2020-06-30 13F FORMFACTOR Cmn Call 21,400 -2.28 628 42.73 n/a n/a n/a
2020-05-15 2020-03-31 13F FORMFACTOR Cmn Call 21,900 114.71 440 66.04 n/a n/a n/a
2020-02-14 2019-12-31 13F FORMFACTOR Cmn Call 10,200 -31.08 265 -3.99 n/a n/a n/a
2019-11-14 2019-09-30 13F FORMFACTOR Cmn Call 14,800 0.00 276 18.97 n/a n/a n/a
2019-08-14 2019-06-30 13F FORMFACTOR Cmn Call 14,800 232 n/a n/a n/a
2018-08-14 2018-06-30 13F/A FORMFACTOR Cmn Call 0 -100.00 0 -100.00 n/a n/a n/a
2018-05-14 2018-03-31 13F/A FORMFACTOR Cmn Call 15,600 30.00 213 13.30 n/a n/a n/a
2018-05-11 2018-03-31 13F FORMFACTOR Cmn Call 15,600 213 n/a n/a n/a
2018-02-09 2017-12-31 13F FORMFACTOR Cmn Call 12,000 -46.67 188 -50.40 n/a n/a n/a
2017-11-09 2017-09-30 13F FORMFACTOR Cmn Call 22,500 77.17 379 152.67 n/a n/a n/a
2017-05-12 2017-03-31 13F FORMFACTOR Cmn Call 12,700 18.69 150 25.00 n/a n/a n/a
2017-02-10 2016-12-31 13F FORMFACTOR Cmn Call 10,700 -45.41 120 -43.66 n/a n/a n/a
2017-01-31 2016-09-30 13F/A FORMFACTOR Cmn Call 19,600 88.46 213 129.03 n/a n/a n/a
2016-11-10 2016-09-30 13F FORMFACTOR INC CMN STK Cmn Call 19,600 213 n/a n/a n/a
2017-01-31 2016-06-30 13F/A FORMFACTOR Cmn Call 10,400 -1.89 93 20.78 n/a n/a n/a
2016-08-12 2016-06-30 13F FORMFACTOR INC CMN STK Cmn Call 10,400 93 n/a n/a n/a
2017-01-31 2016-03-31 13F/A FORMFACTOR Cmn Call 10,600 -8.62 77 -25.96 n/a n/a n/a
2016-05-13 2016-03-31 13F FORMFACTOR INC CMN STK Cmn Call 10,600 77 n/a n/a n/a
2017-01-31 2015-12-31 13F/A FORMFACTOR Cmn Call 11,600 176.19 104 271.43 n/a n/a n/a
2016-02-12 2015-12-31 13F FORMFACTOR INC CMN STK Cmn Call 11,600 104 n/a n/a n/a
2015-11-16 2015-09-30 13F FORMFACTOR INC CMN STK Cmn Call 4,200 -32.26 28 -50.88 n/a n/a n/a
2015-08-14 2015-06-30 13F FORMFACTOR INC CMN STK Cmn Call 6,200 31.91 57 35.71 n/a n/a n/a
2015-05-15 2015-03-31 13F FORMFACTOR INC CMN STK Cmn Call 4,700 80.77 42 90.91 n/a n/a n/a
2015-02-17 2014-12-31 13F FORMFACTOR INC CMN STK Cmn Call 2,600 85.71 22 120.00 n/a n/a n/a
2014-11-14 2014-09-30 13F FORMFACTOR INC CMN STK Cmn Call 1,400 -81.08 10 -83.87 n/a n/a n/a
2014-08-14 2014-06-30 13F FORMFACTOR INC CMN STK Cmn Call 7,400 -3.90 62 26.53 n/a n/a n/a
2014-05-15 2014-03-31 13F FORMFACTOR INC CMN STK Cmn Call 7,700 0.00 49 6.52 n/a n/a n/a
2014-02-14 2013-12-31 13F FORMFACTOR INC CMN STK Cmn Call 7,700 -70.94 46 -74.73 n/a n/a n/a
2013-11-14 2013-09-30 13F FORMFACTOR INC CMN STK Cmn Call 26,500 46.41 182 49.18 n/a n/a n/a
2013-08-14 2013-06-30 13F FORMFACTOR INC CMN STK Cmn Call 18,100 122 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-15 2026-03-31 13F FORMFACTOR COM Put 31,700 8.19 3,075 88.13 n/a n/a n/a
2026-02-17 2025-12-31 13F FORMFACTOR COM Put 29,300 -4.25 1,634 46.68 n/a n/a n/a
2025-11-14 2025-09-30 13F FORMFACTOR COM Put 30,600 13.33 1,114 19.91 n/a n/a n/a
2025-08-14 2025-06-30 13F FORMFACTOR COM Put 27,000 -74.24 929 -68.66 n/a n/a n/a
2025-05-15 2025-03-31 13F FORMFACTOR COM Put 104,800 199.43 2,965 92.47 n/a n/a n/a
2025-02-14 2024-12-31 13F FORMFACTOR COM Put 35,000 139.73 1,540 129.51 n/a n/a n/a
2024-11-14 2024-09-30 13F FORMFACTOR COM Put 14,600 92.11 672 45.87 n/a n/a n/a
2024-08-14 2024-06-30 13F FORMFACTOR COM Put 7,600 -14.61 460 13.30 n/a n/a n/a
2024-05-15 2024-03-31 13F FORMFACTOR COM Put 8,900 456.25 406 515.15 n/a n/a n/a
2024-02-14 2023-12-31 13F FORMFACTOR COM Put 1,600 60.00 67 94.12 n/a n/a n/a
2023-11-14 2023-09-30 13F FORMFACTOR COM Put 1,000 -86.11 35 -86.18 n/a n/a n/a
2023-08-14 2023-06-30 13F FORMFACTOR COM Put 7,200 50.00 246 61.84 n/a n/a n/a
2023-05-15 2023-03-31 13F FORMFACTOR COM Put 4,800 200.00 153 334.29 n/a n/a n/a
2023-02-14 2022-12-31 13F FORMFACTOR COM Put 1,600 36 n/a n/a n/a
2022-02-14 2021-12-31 13F FORMFACTOR Cmn Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-11-15 2021-09-30 13F FORMFACTOR Cmn Put 15,200 -42.42 567 -41.12 n/a n/a n/a
2021-08-16 2021-06-30 13F FORMFACTOR COM Put 26,400 -25.00 963 -39.36 n/a n/a n/a
2021-05-21 2021-03-31 13F/A FORMFACTOR COM Put 35,200 144.44 1,588 156.54 n/a n/a n/a
2021-05-17 2021-03-31 13F FORMFACTOR COM Put 35,200 1,588 n/a n/a n/a
2021-02-16 2020-12-31 13F FORMFACTOR COM Put 14,400 619 n/a n/a n/a
2018-08-14 2018-06-30 13F/A FORMFACTOR Cmn Put 0 -100.00 0 -100.00 n/a n/a n/a
2018-05-14 2018-03-31 13F/A FORMFACTOR Cmn Put 14,600 -27.72 199 -37.03 n/a n/a n/a
2018-05-11 2018-03-31 13F FORMFACTOR Cmn Put 14,600 199 n/a n/a n/a
2018-02-09 2017-12-31 13F FORMFACTOR Cmn Put 20,200 316 n/a n/a n/a
2017-01-31 2015-12-31 13F/A FORMFACTOR INC CMN STK Cmn Put 0 -100.00 0 -100.00 n/a n/a n/a
2015-11-16 2015-09-30 13F FORMFACTOR INC CMN STK Cmn Put 200 -95.00 1 -97.30 n/a n/a n/a
2015-08-14 2015-06-30 13F FORMFACTOR INC CMN STK Cmn Put 4,000 -52.38 37 -50.67 n/a n/a n/a
2015-05-15 2015-03-31 13F FORMFACTOR INC CMN STK Cmn Put 8,400 250.00 75 257.14 n/a n/a n/a
2015-02-17 2014-12-31 13F FORMFACTOR INC CMN STK Cmn Put 2,400 -11.11 21 10.53 n/a n/a n/a
2014-11-14 2014-09-30 13F FORMFACTOR INC CMN STK Cmn Put 2,700 170.00 19 137.50 n/a n/a n/a
2014-08-14 2014-06-30 13F FORMFACTOR INC CMN STK Cmn Put 1,000 -50.00 8 -38.46 n/a n/a n/a
2014-05-15 2014-03-31 13F FORMFACTOR INC CMN STK Cmn Put 2,000 -20.00 13 -13.33 n/a n/a n/a
2014-02-14 2013-12-31 13F FORMFACTOR INC CMN STK Cmn Put 2,500 -10.71 15 -21.05 n/a n/a n/a
2013-11-14 2013-09-30 13F FORMFACTOR INC CMN STK Cmn Put 2,800 -72.00 19 -72.06 n/a n/a n/a
2013-08-14 2013-06-30 13F FORMFACTOR INC CMN STK Cmn Put 10,000 68 n/a n/a n/a
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.