Flowserve Corporation
US ˙ NYSE ˙ US34354P1057

SecurityFLS / Flowserve Corporation
InstitutionGroup One Trading, L.p.
Latest Disclosed Ownership0 shares
Latest Disclosed Value $ 0
Group One Trading, L.p. ownership in FLS / Flowserve Corporation

On February 11, 2026 - Group One Trading, L.p. filed a 13F-HR form disclosing ownership of 0 shares of Flowserve Corporation (US:FLS) valued at $0 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 12, 2025 disclosing 299 shares of Flowserve Corporation. This represents a change in shares of -100.00% during the quarter. The current value of the position is $0 USD.

Group One Trading, L.p. has a history of taking positions in derivatives of the underlying security (FLS) in the form of stock options. The firm currently holds call options representing 11,900 of underlying shares valued at $825,622 USD and put options representing 4,900 of underlying shares valued at $339,962 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.

FLS / Flowserve Corporation 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)
2026-02-11 2025-12-31 13F FLOWSERVE COM 34354P105 0 -299 -100.00 0 -100.00
2025-11-12 2025-09-30 13F FLOWSERVE COM 34354P105 299 299 16 0.0000
2025-08-14 2025-06-30 13F FLOWSERVE COM 34354P105 0 -6,300 -100.00 0 -100.00
2025-05-14 2025-03-31 13F FLOWSERVE COM 34354P105 6,300 4,840 331.51 308 269.88 0.0009
2025-05-14 2024-12-31 13F/A-1 FLOWSERVE COM 34354P105 1,460 1,460 84 0.0002
2025-02-14 2024-12-31 13F FLOWSERVE COM 34354P105 1,460 1,460 84 0.0002
2023-08-09 2023-06-30 13F FLOWSERVE COM 34354P105 0 -262 -100.00 0 -100.00
2023-05-12 2023-03-31 13F FLOWSERVE COM 34354P105 262 -354 -57.47 9 -55.56 0.0000
2023-02-09 2022-12-31 13F FLOWSERVE COM 34354P105 616 -1,489 -70.74 19 -64.71 0.0000
2022-11-09 2022-09-30 13F FLOWSERVE COM 34354P105 2,105 -1,600 -43.18 51 -51.89 0.0001
2022-08-11 2022-06-30 13F FLOWSERVE COM 34354P105 3,705 1,000 36.97 106 9.28 0.0002
2022-05-12 2022-03-31 13F FLOWSERVE COM 34354P105 2,705 -2,046 -43.06 97 -33.10 0.0001
2022-02-11 2021-12-31 13F FLOWSERVE COM 34354P105 4,751 -100 -2.06 145 -13.69 0.0001
2021-11-12 2021-09-30 13F FLOWSERVE COM 34354P105 4,851 2,100 76.34 168 51.35 0.0002
2021-08-10 2021-06-30 13F FLOWSERVE COM 34354P105 2,751 1,779 183.02 111 192.11 0.0001
2021-05-12 2021-03-31 13F FLOWSERVE COM 34354P105 972 972 38 0.0001
2020-08-13 2020-06-30 13F FLOWSERVE COM 34354P105 0 -200 -100.00 0 -100.00
2020-05-13 2020-03-31 13F FLOWSERVE COM 34354P105 200 -2,746 -93.21 5 -96.60 0.0000
2020-02-10 2019-12-31 13F FLOWSERVE COM 34354P105 2,946 2,946 147 0.0010
2018-05-16 2018-03-31 13F/A-1 FLOWSERVE COM 34354P105 0 -4,091 -100.00 0 -100.00
2018-02-09 2017-12-31 13F FLOWSERVE COM 34354P105 4,091 3,524 621.52 172 616.67 0.0012
2017-11-15 2017-09-30 13F FLOWSERVE COM 34354P105 567 -77 -11.96 24 -20.00 0.0002
2017-08-14 2017-06-30 13F FLOWSERVE COM 34354P105 644 644 30 0.0003
2015-11-06 2015-09-30 13F FLOWSERVE COM 34354P105 0 -229 -100.00 0 -100.00
2015-08-11 2015-06-30 13F FLOWSERVE COM 34354P105 229 -9,471 -97.64 12 -97.81 0.0002
2015-05-14 2015-03-31 13F FLOWSERVE COM 34354P105 9,700 9,700 548 0.0086
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
(%)
2026-02-11 2025-12-31 13F FLOWSERVE COM Call 11,900 95.08 826 154.63 n/a n/a n/a
2025-11-12 2025-09-30 13F FLOWSERVE COM Call 6,100 64.86 324 67.88 n/a n/a n/a
2025-08-14 2025-06-30 13F FLOWSERVE COM Call 3,700 -21.28 194 -15.72 n/a n/a n/a
2025-05-14 2025-03-31 13F FLOWSERVE COM Call 4,700 571.43 230 472.50 n/a n/a n/a
2025-05-14 2024-12-31 13F/A FLOWSERVE COM Call 700 250.00 40 300.00 n/a n/a n/a
2025-02-14 2024-12-31 13F FLOWSERVE COM Call 700 40 n/a n/a n/a
2024-11-14 2024-09-30 13F FLOWSERVE COM Call 200 -60.00 10 -58.33 n/a n/a n/a
2024-08-14 2024-06-30 13F FLOWSERVE COM Call 500 24 n/a n/a n/a
2024-02-14 2023-12-31 13F FLOWSERVE COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2023-11-09 2023-09-30 13F FLOWSERVE COM Call 19,600 25.64 779 34.54 n/a n/a n/a
2023-08-09 2023-06-30 13F FLOWSERVE COM Call 15,600 766.67 580 849.18 n/a n/a n/a
2023-05-12 2023-03-31 13F FLOWSERVE COM Call 1,800 -28.00 61 -19.74 n/a n/a n/a
2023-02-09 2022-12-31 13F FLOWSERVE COM Call 2,500 257.14 77 347.06 n/a n/a n/a
2022-11-09 2022-09-30 13F FLOWSERVE COM Call 700 -86.27 17 -88.36 n/a n/a n/a
2022-08-11 2022-06-30 13F FLOWSERVE COM Call 5,100 200.00 146 139.34 n/a n/a n/a
2022-05-12 2022-03-31 13F FLOWSERVE COM Call 1,700 -15.00 61 0.00 n/a n/a n/a
2022-02-11 2021-12-31 13F FLOWSERVE COM Call 2,000 -25.93 61 -35.11 n/a n/a n/a
2021-11-12 2021-09-30 13F FLOWSERVE COM Call 2,700 -22.86 94 -33.33 n/a n/a n/a
2021-08-10 2021-06-30 13F FLOWSERVE COM Call 3,500 105.88 141 113.64 n/a n/a n/a
2021-05-12 2021-03-31 13F FLOWSERVE COM Call 1,700 1,600.00 66 1,550.00 n/a n/a n/a
2021-02-10 2020-12-31 13F FLOWSERVE COM Call 100 0.00 4 33.33 n/a n/a n/a
2020-11-12 2020-09-30 13F FLOWSERVE COM Call 100 -66.67 3 -66.67 n/a n/a n/a
2020-08-13 2020-06-30 13F FLOWSERVE COM Call 300 200.00 9 350.00 n/a n/a n/a
2020-05-13 2020-03-31 13F FLOWSERVE COM Call 100 -98.59 2 -99.43 n/a n/a n/a
2020-02-10 2019-12-31 13F FLOWSERVE COM Call 7,100 102.86 353 116.56 n/a n/a n/a
2019-11-12 2019-09-30 13F FLOWSERVE COM Call 3,500 -96.40 163 -96.82 n/a n/a n/a
2019-08-09 2019-06-30 13F FLOWSERVE COM Call 97,300 1,521.67 5,127 1,791.88 n/a n/a n/a
2019-05-14 2019-03-31 13F/A FLOWSERVE COM Call 6,000 -71.01 271 -65.57 n/a n/a n/a
2019-05-13 2019-03-31 13F FLOWSERVE COM Call 6,000 271 n/a n/a n/a
2019-02-05 2018-12-31 13F FLOWSERVE COM Call 20,700 143.53 787 69.25 n/a n/a n/a
2018-11-08 2018-09-30 13F FLOWSERVE COM Call 8,500 465 n/a n/a n/a
2018-08-13 2018-06-30 13F FLOWSERVE COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2018-05-16 2018-03-31 13F/A FLOWSERVE COM Call 2,500 108.33 108 111.76 n/a n/a n/a
2018-05-10 2018-03-31 13F FLOWSERVE COM Call 2,500 108 n/a n/a n/a
2018-02-09 2017-12-31 13F FLOWSERVE COM Call 1,200 140.00 51 142.86 n/a n/a n/a
2017-11-15 2017-09-30 13F FLOWSERVE COM Call 500 21 n/a n/a n/a
2017-08-14 2017-06-30 13F FLOWSERVE COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2017-05-10 2017-03-31 13F FLOWSERVE COM Call 100 -98.25 5 -98.18 n/a n/a n/a
2017-02-15 2016-12-31 13F FLOWSERVE COM Call 5,700 -49.11 274 -49.26 n/a n/a n/a
2016-11-14 2016-09-30 13F FLOWSERVE COM Call 11,200 1,020.00 540 1,100.00 n/a n/a n/a
2016-08-12 2016-06-30 13F FLOWSERVE COM Call 1,000 0.00 45 2.27 n/a n/a n/a
2016-05-12 2016-03-31 13F FLOWSERVE COM Call 1,000 44 n/a n/a n/a
2016-02-11 2015-12-31 13F FLOWSERVE COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2015-11-20 2015-09-30 13F/A FLOWSERVE COM Call 1,100 1,000.00 45 800.00 n/a n/a n/a
2015-11-06 2015-09-30 13F FLOWSERVE COM Call 1,100 45 n/a n/a n/a
2015-08-11 2015-06-30 13F FLOWSERVE COM Call 100 5 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
(%)
2026-02-11 2025-12-31 13F FLOWSERVE COM Put 4,900 1,125.00 340 1,514.29 n/a n/a n/a
2025-11-12 2025-09-30 13F FLOWSERVE COM Put 400 -91.49 21 -91.46 n/a n/a n/a
2025-08-14 2025-06-30 13F FLOWSERVE COM Put 4,700 246 n/a n/a n/a
2025-05-14 2025-03-31 13F FLOWSERVE COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-05-14 2024-12-31 13F/A FLOWSERVE COM Put 100 6 n/a n/a n/a
2025-02-14 2024-12-31 13F FLOWSERVE COM Put 100 6 n/a n/a n/a
2024-05-10 2024-03-31 13F FLOWSERVE COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2024-02-14 2023-12-31 13F FLOWSERVE COM Put 300 0.00 12 9.09 n/a n/a n/a
2023-11-09 2023-09-30 13F FLOWSERVE COM Put 300 12 n/a n/a n/a
2023-05-12 2023-03-31 13F FLOWSERVE COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2023-02-09 2022-12-31 13F FLOWSERVE COM Put 1,400 0.00 43 23.53 n/a n/a n/a
2022-11-09 2022-09-30 13F FLOWSERVE COM Put 1,400 0.00 34 -15.00 n/a n/a n/a
2022-08-11 2022-06-30 13F FLOWSERVE COM Put 1,400 27.27 40 2.56 n/a n/a n/a
2022-05-12 2022-03-31 13F FLOWSERVE COM Put 1,100 -74.42 39 -70.45 n/a n/a n/a
2022-02-11 2021-12-31 13F FLOWSERVE COM Put 4,300 34.38 132 18.92 n/a n/a n/a
2021-11-12 2021-09-30 13F FLOWSERVE COM Put 3,200 540.00 111 455.00 n/a n/a n/a
2021-08-10 2021-06-30 13F FLOWSERVE COM Put 500 150.00 20 150.00 n/a n/a n/a
2021-05-12 2021-03-31 13F FLOWSERVE COM Put 200 8 n/a n/a n/a
2019-08-09 2019-06-30 13F FLOWSERVE COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2019-05-14 2019-03-31 13F/A FLOWSERVE COM Put 4,300 -12.24 194 4.30 n/a n/a n/a
2019-05-13 2019-03-31 13F FLOWSERVE COM Put 4,300 194 n/a n/a n/a
2019-02-05 2018-12-31 13F FLOWSERVE COM Put 4,900 -46.74 186 -63.02 n/a n/a n/a
2018-11-08 2018-09-30 13F FLOWSERVE COM Put 9,200 76.92 503 139.52 n/a n/a n/a
2018-08-13 2018-06-30 13F FLOWSERVE COM Put 5,200 210 n/a n/a n/a
2018-05-16 2018-03-31 13F/A FLOWSERVE COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2018-02-09 2017-12-31 13F FLOWSERVE COM Put 2,700 114 n/a n/a n/a
2017-05-10 2017-03-31 13F FLOWSERVE COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2017-02-15 2016-12-31 13F FLOWSERVE COM Put 5,100 1,175.00 245 1,189.47 n/a n/a n/a
2016-11-14 2016-09-30 13F FLOWSERVE COM Put 400 19 n/a n/a n/a
2015-11-06 2015-09-30 13F FLOWSERVE COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2015-08-11 2015-06-30 13F FLOWSERVE COM Put 100 -99.71 5 -99.74 n/a n/a n/a
2015-05-14 2015-03-31 13F FLOWSERVE COM Put 34,600 1,955 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.