Diamondback Energy, Inc.
US ˙ NasdaqGS ˙ US25278X1090

SecurityFANG / Diamondback Energy, Inc.
InstitutionSei Investments Co
Latest Disclosed Ownership130,979 shares
Latest Disclosed Value $ 19,689,336
Sei Investments Co reports 10.83% decrease in ownership of FANG / Diamondback Energy, Inc.

On February 13, 2026 - Sei Investments Co filed a 13F-HR form disclosing ownership of 130,979 shares of Diamondback Energy, Inc. (US:FANG) valued at $19,690,073 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 146,895 shares of Diamondback Energy, Inc.. This represents a change in shares of -10.83% during the quarter. The current value of the position is $27,582,868 USD.

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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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 DIAMONDBACK ENERGY COM 25278X109 130,979 -15,916 -10.83 19,689 -6.33 0.0194
2025-11-13 2025-09-30 13F DIAMONDBACK ENERGY COM 25278X109 146,895 -7,687 -4.97 21,021 -1.03 0.0226
2025-08-14 2025-06-30 13F DIAMONDBACK ENERGY COM 25278X109 154,582 -14,741 -8.71 21,239 -21.55 0.0246
2025-05-14 2025-03-31 13F/A-1 DIAMONDBACK ENERGY COM 25278X109 169,323 54,811 47.86 27,072 44.31 0.0348
2025-05-13 2025-03-31 13F DIAMONDBACK ENERGY COM 25278X109 112,716 -1,796 18,418 0.0200
2025-02-11 2024-12-31 13F DIAMONDBACK ENERGY COM 25278X109 114,512 -26,378 -18.72 18,760 -22.76 0.0241
2024-11-12 2024-09-30 13F DIAMONDBACK ENERGY COM 25278X109 140,890 -25,794 -15.47 24,289 -27.21 0.0315
2024-08-13 2024-06-30 13F DIAMONDBACK ENERGY COM 25278X109 166,684 -10,263 -5.80 33,367 -4.84 0.0473
2024-05-07 2024-03-31 13F DIAMONDBACK ENERGY COM 25278X109 176,947 -42,496 -19.37 35,064 3.03 0.0514
2024-02-14 2023-12-31 13F DIAMONDBACK ENERGY COM 25278X109 219,443 -10,950 -4.75 34,032 -4.63 0.0546
2023-11-14 2023-09-30 13F DIAMONDBACK ENERGY COM 25278X109 230,393 -3,048 -1.31 35,683 16.36 0.0641
2023-08-11 2023-06-30 13F DIAMONDBACK ENERGY COM 25278X109 233,441 9,181 4.09 30,665 1.15 0.0535
2023-05-12 2023-03-31 13F DIAMONDBACK ENERGY COM 25278X109 224,260 17,917 8.68 30,314 7.41 0.0563
2023-02-10 2022-12-31 13F DIAMONDBACK ENERGY COM 25278X109 206,343 1,219 0.59 28,223 14.22 0.0627
2022-11-14 2022-09-30 13F DIAMONDBACK ENERGY COM 25278X109 205,124 68,992 50.68 24,709 49.79 0.0551
2022-08-15 2022-06-30 13F DIAMONDBACK ENERGY COM 25278X109 136,132 20,179 17.40 16,496 3.67 0.0356
2022-05-13 2022-03-31 13F DIAMONDBACK ENERGY COM 25278X109 115,953 -12,617 -9.81 15,912 14.70 0.0320
2022-02-14 2021-12-31 13F DIAMONDBACK ENERGY COM 25278X109 128,570 -11,713 -8.35 13,873 4.65 0.0260
2021-11-12 2021-09-30 13F DIAMONDBACK ENERGY COM 25278X109 140,283 1,048 0.75 13,256 1.39 0.0278
2021-08-06 2021-06-30 13F DIAMONDBACK ENERGY COM 25278X109 139,235 29,217 26.56 13,074 62.47 0.0290
2021-05-12 2021-03-31 13F DIAMONDBACK ENERGY COM 25278X109 110,018 -21,468 -16.33 8,047 26.49 0.0203
2021-02-08 2020-12-31 13F DIAMONDBACK ENERGY COM 25278X109 131,486 -29,422 -18.28 6,362 31.42 0.0164
2020-12-04 2020-09-30 13F/A-1 DIAMONDBACK ENERGY COM 25278X109 160,908 53,000 49.12 4,841 6.70 0.0140
2020-11-06 2020-09-30 13F DIAMONDBACK ENERGY COM 25278X109 162,218 54,310 4,880 11,749.9550
2020-08-17 2020-06-30 13F/A-1 DIAMONDBACK ENERGY COM 25278X109 107,908 38,726 55.98 4,537 151.50 0.0141
2020-08-11 2020-06-30 13F DIAMONDBACK ENERGY COM 25278X109 179,690 110,508 16,429 44,564.5370
2020-05-14 2020-03-31 13F DIAMONDBACK ENERGY COM 25278X109 69,182 -180,215 -72.26 1,804 -92.21 0.0066
2020-02-06 2019-12-31 13F DIAMONDBACK ENERGY COM 25278X109 249,397 121,087 94.37 23,159 100.51 0.0691
2019-11-12 2019-09-30 13F DIAMONDBACK ENERGY COM 25278X109 128,310 -74,016 -36.58 11,550 -47.63 0.0295
2019-08-14 2019-06-30 13F DIAMONDBACK ENERGY COM 25278X109 202,326 43,059 27.04 22,053 36.34 0.0720
2019-05-15 2019-03-31 13F DIAMONDBACK ENERGY COM 25278X109 159,267 91,528 135.12 16,175 133.41 0.0543
2019-02-13 2018-12-31 13F DIAMONDBACK ENERGY COM 25278X109 67,739 52,539 345.65 6,930 237.23 0.0247
2018-11-08 2018-09-30 13F DIAMONDBACK ENERGY COM 25278X109 15,200 -2,029 -11.78 2,055 -9.35 0.0074
2018-08-03 2018-06-30 13F DIAMONDBACK ENERGY COM 25278X109 17,229 -63,264 -78.60 2,267 -77.74 0.0077
2018-05-11 2018-03-31 13F DIAMONDBACK ENERGY COM 25278X109 80,493 -76,830 -48.84 10,184 -48.73 0.0390
2018-02-08 2017-12-31 13F DIAMONDBACK ENERGY COM 25278X109 157,323 39,657 33.70 19,863 72.32 0.0690
2017-11-06 2017-09-30 13F DIAMONDBACK ENERGY COM 25278X109 117,666 -100,487 -46.06 11,527 -40.50 0.0410
2017-07-31 2017-06-30 13F DIAMONDBACK ENERGY COM 25278X109 218,153 47,963 28.18 19,374 9.76 0.0772
2017-05-05 2017-03-31 13F DIAMONDBACK ENERGY COM 25278X109 170,190 -35,877 -17.41 17,651 -15.24 0.0774
2017-02-02 2016-12-31 13F DIAMONDBACK ENERGY COM 25278X109 206,067 22,849 12.47 20,825 17.74 0.1008
2016-11-04 2016-09-30 13F DIAMONDBACK ENERGY COM 25278X109 183,218 3,688 2.05 17,688 8.02 0.0899
2016-08-11 2016-06-30 13F DIAMONDBACK ENERGY COM 25278X109 179,530 99,959 125.62 16,375 166.65 0.0982
2016-05-10 2016-03-31 13F/A-1 DIAMONDBACK ENERGY COM 25278X109 79,571 55,743 233.94 6,141 285.26 0.0382
2016-02-03 2015-12-31 13F DIAMONDBACK ENERGY COM 25278X109 23,828 -6,716 -21.99 1,594 -19.25 0.0097
2015-11-02 2015-09-30 13F/A-1 DIAMONDBACK ENERGY COM 25278X109 30,544 24,563 410.68 1,974 338.67 0.0181
2015-10-30 2015-09-30 13F DIAMONDBACK ENERGY COM 25278X109 30,544 1,975
2015-08-07 2015-06-30 13F/A-1 DIAMONDBACK ENERGY COM 25278X109 5,981 -2,265 -27.47 450 -28.80 0.0041
2015-08-04 2015-06-30 13F DIAMONDBACK ENERGY COM 25278X109 5,981 -2,265 450 0.0041
2015-05-14 2015-03-31 13F/A-1 DIAMONDBACK ENERGY COM 25278X109 8,246 1,077 15.02 632 47.66 0.0055
2015-05-01 2015-03-31 13F DIAMONDBACK ENERGY COM 25278X109 8,246 632
2015-02-10 2014-12-31 13F DIAMONDBACK ENERGY COM 25278X109 7,169 7,169 428 0.0038
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.