Mattel, Inc.
US ˙ NasdaqGS ˙ US5770811025

SecurityMAT / Mattel, Inc.
InstitutionSei Investments Co
Latest Disclosed Ownership1,041,679 shares
Latest Disclosed Value $ 20,666,974
Sei Investments Co ownership in MAT / Mattel, Inc.

On February 13, 2026 - Sei Investments Co filed a 13F-HR form disclosing ownership of 1,041,679 shares of Mattel, Inc. (US:MAT) valued at $20,666,911 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 67,387 shares of Mattel, Inc.. This represents a change in shares of 1,445.82% during the quarter. The current value of the position is $14,937,677 USD.

Sei Investments Co has a history of taking positions in derivatives of the underlying security (MAT) in the form of stock options.

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.

MAT / Mattel, 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)
2026-02-13 2025-12-31 13F MATTEL COM 577081102 1,041,679 974,292 1,445.82 20,667 1,722.40
2025-11-13 2025-09-30 13F MATTEL COM 577081102 67,387 21,651 47.34 1,134 25.86 0.0012
2025-08-14 2025-06-30 13F MATTEL COM 577081102 45,736 -3,884 -7.83 902 -6.54 0.0010
2025-05-14 2025-03-31 13F/A-1 MATTEL COM 577081102 49,620 4,686 10.43 964 21.11 0.0012
2025-05-13 2025-03-31 13F MATTEL COM 577081102 44,978 44 798 0.0009
2025-02-11 2024-12-31 13F MATTEL COM 577081102 44,934 -149,703 -76.91 797 -78.53 0.0010
2024-11-12 2024-09-30 13F MATTEL COM 577081102 194,637 -32 -0.02 3,708 17.12 0.0048
2024-08-13 2024-06-30 13F MATTEL COM 577081102 194,669 1,878 0.97 3,165 -17.12 0.0045
2024-05-07 2024-03-31 13F MATTEL COM 577081102 192,791 -2,463 -1.26 3,819 3.61 0.0056
2024-02-14 2023-12-31 13F MATTEL COM 577081102 195,254 -2,998 -1.51 3,686 -15.59 0.0059
2023-11-14 2023-09-30 13F MATTEL COM 577081102 198,252 -17,251 -8.00 4,367 3.73 0.0078
2023-08-11 2023-06-30 13F MATTEL COM 577081102 215,503 -8,804 -3.92 4,211 1.96 0.0073
2023-05-12 2023-03-31 13F MATTEL COM 577081102 224,307 54,742 32.28 4,129 36.50 0.0077
2023-02-10 2022-12-31 13F MATTEL COM 577081102 169,565 -205,440 -54.78 3,025 -57.40 0.0067
2022-11-14 2022-09-30 13F MATTEL COM 577081102 375,005 -443,831 -54.20 7,101 -60.97 0.0158
2022-08-15 2022-06-30 13F MATTEL COM 577081102 818,836 38,954 4.99 18,192 5.24 0.0393
2022-05-13 2022-03-31 13F MATTEL COM 577081102 779,882 342,047 78.12 17,286 83.11 0.0347
2022-02-14 2021-12-31 13F MATTEL COM 577081102 437,835 -38,242 -8.03 9,440 6.93 0.0177
2021-11-12 2021-09-30 13F MATTEL COM 577081102 476,077 -106,196 -18.24 8,828 -24.60 0.0185
2021-08-06 2021-06-30 13F MATTEL COM 577081102 582,273 348,141 148.69 11,708 157.89 0.0260
2021-05-12 2021-03-31 13F MATTEL COM 577081102 234,132 0 0.00 4,540 11.14 0.0114
2021-02-08 2020-12-31 13F MATTEL COM 577081102 234,132 182 0.08 4,085 49.25 0.0106
2020-12-04 2020-09-30 13F/A-1 MATTEL COM 577081102 233,950 -42,206 -15.28 2,737 2.51 0.0079
2020-11-06 2020-09-30 13F MATTEL COM 577081102 233,956 -42,200 2,737 6,590.0875
2020-08-17 2020-06-30 13F/A-1 MATTEL COM 577081102 276,156 11,374 4.30 2,670 14.44 0.0083
2020-08-11 2020-06-30 13F MATTEL COM 577081102 422,364 157,582 5,723 15,523.9421
2020-05-14 2020-03-31 13F MATTEL COM 577081102 264,782 -157,582 -37.31 2,333 -59.23 0.0086
2020-02-06 2019-12-31 13F MATTEL COM 577081102 422,364 158 0.04 5,723 19.01 0.0171
2019-11-12 2019-09-30 13F MATTEL COM 577081102 422,206 -9,455 -2.19 4,809 -0.62 0.0123
2019-08-14 2019-06-30 13F MATTEL COM 577081102 431,661 -13,884 -3.12 4,839 -16.45 0.0158
2019-05-15 2019-03-31 13F MATTEL COM 577081102 445,545 -6,802 -1.50 5,792 -18.45 0.0195
2019-02-13 2018-12-31 13F MATTEL COM 577081102 452,347 0 0.00 7,102 0.00 0.0253
2018-11-08 2018-09-30 13F MATTEL COM 577081102 452,347 -20,339 -4.30 7,102 -8.49 0.0257
2018-08-03 2018-06-30 13F MATTEL COM 577081102 472,686 -23,391 -4.72 7,761 18.96 0.0264
2018-05-11 2018-03-31 13F MATTEL COM 577081102 496,077 -1,646,095 -76.84 6,524 -80.20 0.0250
2018-02-08 2017-12-31 13F MATTEL COM 577081102 2,142,172 1,266,982 144.77 32,946 143.18 0.1144
2017-11-06 2017-09-30 13F MATTEL COM 577081102 875,190 217,266 33.02 13,548 -4.36 0.0482
2017-07-31 2017-06-30 13F MATTEL COM 577081102 657,924 319,438 94.37 14,166 63.43 0.0565
2017-05-05 2017-03-31 13F MATTEL COM 577081102 338,486 -126,030 -27.13 8,668 -32.27 0.0380
2017-02-02 2016-12-31 13F MATTEL COM 577081102 464,516 24,904 5.66 12,797 -3.86 0.0620
2016-11-04 2016-09-30 13F MATTEL COM 577081102 439,612 15,906 3.75 13,311 0.39 0.0676
2016-08-11 2016-06-30 13F MATTEL COM 577081102 423,706 130,283 44.40 13,259 34.40 0.0795
2016-05-10 2016-03-31 13F/A-1 MATTEL COM 577081102 293,423 -285,351 -49.30 9,865 -37.27 0.0614
2016-02-03 2015-12-31 13F MATTEL COM 577081102 578,774 189,116 48.53 15,725 91.63 0.0958
2015-11-02 2015-09-30 13F/A-1 MATTEL COM 577081102 389,658 237,979 156.90 8,206 110.57 0.0753
2015-10-30 2015-09-30 13F MATTEL COM 577081102 389,658 8,207
2015-08-07 2015-06-30 13F/A-1 MATSON PUT 577081102 0 -154,806 -100.00 0 -100.00
2015-08-07 2015-06-30 13F/A-1 MATTEL COM 577081102 151,679 -3,127 -2.02 3,897 10.21 0.0352
2015-08-04 2015-06-30 13F MATTEL COM 577081102 151,679 -3,127 3,897 0.0352
2015-05-14 2015-03-31 13F/A-1 MATTEL COM 577081102 154,806 -11,848 -7.11 3,536 -31.39 0.0307
2015-05-01 2015-03-31 13F MATSON PUT 577081102 154,806 154,806 3,536 0.0307
2015-02-10 2014-12-31 13F MATTEL COM 577081102 166,654 166,654 5,154 0.0456
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
(%)
2015-08-07 2015-06-30 13F/A MATSON PUT 0 -100.00 0 -100.00 n/a n/a n/a
2015-05-01 2015-03-31 13F MATSON PUT 154,806 3,536 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.