Biogen Inc.
MX ˙ BMV ˙ US09062X1037
SecurityMX:BIIB / Biogen Inc.
InstitutionMillennium Management Llc
ManagerIsrael Englander
Latest Disclosed Ownership93,964 shares
Latest Disclosed Value $ 17,226,420
Millennium Management Llc ownership in BIIB / Biogen Inc.

On May 15, 2026 - Millennium Management Llc filed a 13F-HR form disclosing ownership of 93,964 shares of Biogen Inc. (MX:BIIB) valued at $17,226,420 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 1,125,586 shares of Biogen Inc.. This represents a change in shares of -91.65% during the quarter.

Millennium Management Llc has a history of taking positions in derivatives of the underlying security (BIIB) in the form of stock options. The firm currently holds call options representing 83,900 of underlying shares valued at $15,381,387 USD and put options representing 103,900 of underlying shares valued at $19,047,987 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.

MX:BIIB / Biogen 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 BIOGEN COM 09062X103 93,964 -1,031,622 -91.65 17,226 -91.30 0.0072
2026-02-17 2025-12-31 13F BIOGEN COM 09062X103 1,125,586 14,396 1.30 198,092 27.26 0.0833
2025-11-14 2025-09-30 13F BIOGEN COM 09062X103 1,111,190 435,688 64.50 155,655 83.48 0.0664
2025-08-14 2025-06-30 13F BIOGEN COM 09062X103 675,502 251,505 59.32 84,836 46.22 0.0410
2025-05-15 2025-03-31 13F BIOGEN COM 09062X103 423,997 -119,847 -22.04 58,020 -30.24 0.0309
2025-02-14 2024-12-31 13F BIOGEN COM 09062X103 543,844 145,708 36.60 83,165 7.76 0.0406
2024-11-14 2024-09-30 13F BIOGEN COM 09062X103 398,136 158,289 66.00 77,175 38.80 0.0366
2024-08-14 2024-06-30 13F BIOGEN COM 09062X103 239,847 63,435 35.96 55,601 46.17 0.0257
2024-05-15 2024-03-31 13F BIOGEN COM 09062X103 176,412 171,877 3,790.01 38,040 3,142.88 0.0162
2024-02-14 2023-12-31 13F BIOGEN COM 09062X103 4,535 -73,609 -94.20 1,174 -94.16 0.0005
2023-11-14 2023-09-30 13F BIOGEN COM 09062X103 78,144 33,970 76.90 20,084 59.62 0.0101
2023-08-14 2023-06-30 13F BIOGEN COM 09062X103 44,174 -469,218 -91.40 12,583 -91.19 0.0062
2023-05-15 2023-03-31 13F BIOGEN COM 09062X103 513,392 174,807 51.63 142,738 52.24 0.0818
2023-02-14 2022-12-31 13F BIOGEN COM 09062X103 338,585 -574,120 -62.90 93,761 -61.52 0.0519
2022-11-14 2022-09-30 13F BIOGEN COM 09062X103 912,705 331,058 56.92 243,692 105.44 0.1441
2022-08-15 2022-06-30 13F BIOGEN COM 09062X103 581,647 -22,566 -3.73 118,621 -6.78 0.0736
2022-05-16 2022-03-31 13F BIOGEN COM 09062X103 604,213 191,325 46.34 127,247 28.45 0.0675
2022-02-14 2021-12-31 13F BIOGEN COM 09062X103 412,888 141,069 51.90 99,060 28.78 0.0503
2021-11-15 2021-09-30 13F BIOGEN COM 09062X103 271,819 -35,210 -11.47 76,922 -27.65 0.0461
2021-08-16 2021-06-30 13F BIOGEN COM 09062X103 307,029 152,271 98.39 106,315 145.57 0.0652
2021-05-17 2021-03-31 13F BIOGEN COM 09062X103 154,758 -94,658 -37.95 43,294 -29.11 0.0310
2021-02-16 2020-12-31 13F BIOGEN COM 09062X103 249,416 -28,043 -10.11 61,072 -22.41 0.0441
2020-11-16 2020-09-30 13F BIOGEN COM 09062X103 277,459 177,339 177.13 78,710 193.84 0.0969
2020-08-14 2020-06-30 13F BIOGEN COM 09062X103 100,120 27,785 38.41 26,787 17.05 0.0367
2020-05-14 2020-03-31 13F BIOGEN COM 09062X103 72,335 -447,279 -86.08 22,885 -85.16 0.0514
2020-02-14 2019-12-31 13F BIOGEN COM 09062X103 519,614 -134,114 -20.52 154,185 1.30 0.1929
2019-11-14 2019-09-30 13F BIOGEN COM 09062X103 653,728 178,008 37.42 152,200 36.80 0.2406
2019-08-15 2019-06-30 13F/A-1 BIOGEN COM 09062X103 475,720 367,962 341.47 111,257 336.78 0.1673
2019-08-14 2019-06-30 13F KRATOS DEFENSE & SEC SOLUTIO COM NEW 09062X103 554,119 367,962 113,052
2019-05-14 2019-03-31 13F BIOGEN COM 09062X103 107,758 30,916 40.23 25,472 10.16 0.0381
2019-02-15 2018-12-31 13F/A-1 BIOGEN COM 09062X103 76,842 -189,643 -71.16 23,123 -75.44 0.0361
2019-02-14 2018-12-31 13F BIOGEN COM 09062X103 76,842 23,123
2018-11-14 2018-09-30 13F BIOGEN COM 09062X103 266,485 111,438 71.87 94,152 109.22 0.1154
2018-08-14 2018-06-30 13F BIOGEN COM 09062X103 155,047 -289,001 -65.08 45,001 -62.99 0.0587
2018-05-15 2018-03-31 13F BIOGEN COM 09062X103 444,048 389,965 721.05 121,589 605.72 0.1622
2018-02-14 2017-12-31 13F BIOGEN COM 09062X103 54,083 -133,645 -71.19 17,229 -70.69 0.0238
2017-11-14 2017-09-30 13F BIOGEN COM 09062X103 187,728 -156,551 -45.47 58,781 -37.08 0.0896
2017-08-14 2017-06-30 13F BIOGEN COM 09062X103 344,279 172,540 100.47 93,424 98.96 0.1667
2017-05-15 2017-03-31 13F BIOGEN COM 09062X103 171,739 -315,771 -64.77 46,957 -66.03 0.0860
2017-02-14 2016-12-31 13F BIOGEN COM 09062X103 487,510 -92,427 -15.94 138,248 -23.85 0.2895
2016-11-14 2016-09-30 13F BIOGEN COM 09062X103 579,937 -225,041 -27.96 181,538 -6.74 0.3044
2016-08-15 2016-06-30 13F BIOGEN COM 09062X103 804,978 -26,005 -3.13 194,660 -10.01 0.4456
2016-05-16 2016-03-31 13F BIOGEN COM 09062X103 830,983 -219,701 -20.91 216,321 -32.79 0.5407
2016-02-16 2015-12-31 13F BIOGEN COM 09062X103 1,050,684 425,850 68.15 321,877 76.53 0.6767
2015-11-16 2015-09-30 13F BIOGEN COM 09062X103 624,834 -295,256 -32.09 182,333 -50.94 0.3531
2015-08-14 2015-06-30 13F BIOGEN COM 09062X103 920,090 440,068 91.68 371,661 83.37 0.7030
2015-05-15 2015-03-31 13F BIOGEN COM 09062X103 480,022 27,318 6.03 202,684 31.90 0.3771
2015-02-17 2014-12-31 13F BIOGEN IDEC COM 09062X103 452,704 7,041 1.58 153,670 4.23 0.3256
2014-11-14 2014-09-30 13F BIOGEN IDEC COM 09062X103 445,663 352,491 378.32 147,430 401.84 0.3730
2014-08-14 2014-06-30 13F BIOGEN IDEC COM 09062X103 93,172 -93,909 -50.20 29,378 -48.66 0.0814
2014-05-15 2014-03-31 13F BIOGEN IDEC COM 09062X103 187,081 -50,638 -21.30 57,222 -13.90 0.1658
2014-02-14 2013-12-31 13F BIOGEN IDEC COM 09062X103 237,719 222,881 1,502.10 66,460 1,760.58 0.2097
2013-11-14 2013-09-30 13F BIOGEN IDEC COM 09062X103 14,838 -20,853 -58.43 3,572 -53.50 0.0115
2013-08-14 2013-06-30 13F BIOGEN IDEC COM 09062X103 35,691 35,691 7,681 0.0235
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 BIOGEN COM Call 83,900 -17.01 15,381 -13.55 n/a n/a n/a
2026-02-17 2025-12-31 13F BIOGEN COM Call 101,100 18.11 17,793 48.39 n/a n/a n/a
2025-11-14 2025-09-30 13F BIOGEN COM Call 85,600 245.16 11,991 285.04 n/a n/a n/a
2025-08-14 2025-06-30 13F BIOGEN COM Call 24,800 -55.71 3,115 -59.36 n/a n/a n/a
2025-05-15 2025-03-31 13F BIOGEN COM Call 56,000 95.12 7,663 74.64 n/a n/a n/a
2025-02-14 2024-12-31 13F BIOGEN COM Call 28,700 -3.04 4,389 -23.51 n/a n/a n/a
2024-11-14 2024-09-30 13F BIOGEN COM Call 29,600 -65.38 5,738 -71.05 n/a n/a n/a
2024-08-14 2024-06-30 13F BIOGEN COM Call 85,500 91.70 19,821 106.09 n/a n/a n/a
2024-05-15 2024-03-31 13F BIOGEN COM Call 44,600 17.99 9,617 -1.68 n/a n/a n/a
2024-02-14 2023-12-31 13F BIOGEN COM Call 37,800 10.85 9,782 11.60 n/a n/a n/a
2023-11-14 2023-09-30 13F BIOGEN COM Call 34,100 -48.72 8,764 -53.73 n/a n/a n/a
2023-08-14 2023-06-30 13F BIOGEN COM Call 66,500 117.32 18,943 122.64 n/a n/a n/a
2023-05-15 2023-03-31 13F BIOGEN COM Call 30,600 -49.25 8,508 -49.05 n/a n/a n/a
2023-02-14 2022-12-31 13F BIOGEN COM Call 60,300 -52.37 16,698 -50.60 n/a n/a n/a
2022-11-14 2022-09-30 13F BIOGEN COM Call 126,600 33,802 n/a n/a n/a
2022-05-16 2022-03-31 13F BIOGEN COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-02-14 2021-12-31 13F BIOGEN COM Call 80,600 -36.64 19,338 -46.28 n/a n/a n/a
2021-11-15 2021-09-30 13F BIOGEN COM Call 127,200 942.62 35,996 752.18 n/a n/a n/a
2021-08-16 2021-06-30 13F BIOGEN COM Call 12,200 -71.56 4,224 -64.80 n/a n/a n/a
2021-05-17 2021-03-31 13F BIOGEN COM Call 42,900 -61.52 12,001 -56.04 n/a n/a n/a
2021-02-16 2020-12-31 13F BIOGEN COM Call 111,500 10,036.36 27,302 8,650.64 n/a n/a n/a
2020-11-16 2020-09-30 13F BIOGEN COM Call 1,100 -91.27 312 -90.74 n/a n/a n/a
2020-08-14 2020-06-30 13F BIOGEN COM Call 12,600 3,371 n/a n/a n/a
2020-05-14 2020-03-31 13F BIOGEN COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2020-02-14 2019-12-31 13F BIOGEN COM Call 11,500 -93.99 3,412 -92.35 n/a n/a n/a
2019-11-14 2019-09-30 13F BIOGEN COM Call 191,500 -31.39 44,585 -31.69 n/a n/a n/a
2019-08-15 2019-06-30 13F/A BIOGEN COM Call 279,100 7.72 65,273 6.58 n/a n/a n/a
2019-08-14 2019-06-30 13F BIOGEN COM Call 279,100 65,273 n/a n/a n/a
2019-05-14 2019-03-31 13F BIOGEN COM Call 259,100 100.70 61,246 57.65 n/a n/a n/a
2019-02-15 2018-12-31 13F/A BIOGEN COM Call 129,100 1,318.68 38,849 1,108.37 n/a n/a n/a
2019-02-14 2018-12-31 13F BIOGEN COM Call 129,100 38,849 n/a n/a n/a
2018-11-14 2018-09-30 13F BIOGEN COM Call 9,100 -54.50 3,215 -44.62 n/a n/a n/a
2018-08-14 2018-06-30 13F BIOGEN COM Call 20,000 -73.33 5,805 -71.73 n/a n/a n/a
2018-05-15 2018-03-31 13F BIOGEN COM Call 75,000 150.00 20,537 114.89 n/a n/a n/a
2018-02-14 2017-12-31 13F BIOGEN COM Call 30,000 9,557 n/a n/a n/a
2017-08-14 2017-06-30 13F BIOGEN COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2017-05-15 2017-03-31 13F BIOGEN COM Call 176,400 6,956.00 48,231 6,702.68 n/a n/a n/a
2017-02-14 2016-12-31 13F BIOGEN COM Call 2,500 709 n/a n/a n/a
2015-08-14 2015-06-30 13F BIOGEN COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2015-05-15 2015-03-31 13F BIOGEN COM Call 30,200 504.00 12,752 812.16 n/a n/a n/a
2014-02-14 2013-12-31 13F BIOGEN IDEC COM Call 5,000 4.17 1,398 20.93 n/a n/a n/a
2013-11-14 2013-09-30 13F BIOGEN IDEC COM Call 4,800 1,156 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 BIOGEN COM Put 103,900 122.48 19,048 131.77 n/a n/a n/a
2026-02-17 2025-12-31 13F BIOGEN COM Put 46,700 -82.11 8,219 -77.52 n/a n/a n/a
2025-11-14 2025-09-30 13F BIOGEN COM Put 261,000 381.55 36,561 437.17 n/a n/a n/a
2025-08-14 2025-06-30 13F BIOGEN COM Put 54,200 -28.12 6,807 -34.03 n/a n/a n/a
2025-05-15 2025-03-31 13F BIOGEN COM Put 75,400 176.19 10,318 147.17 n/a n/a n/a
2025-02-14 2024-12-31 13F BIOGEN COM Put 27,300 -40.00 4,175 -52.67 n/a n/a n/a
2024-11-14 2024-09-30 13F BIOGEN COM Put 45,500 218.18 8,820 166.03 n/a n/a n/a
2024-08-14 2024-06-30 13F BIOGEN COM Put 14,300 -63.80 3,315 -61.08 n/a n/a n/a
2024-05-15 2024-03-31 13F BIOGEN COM Put 39,500 0.00 8,517 -16.67 n/a n/a n/a
2024-02-14 2023-12-31 13F BIOGEN COM Put 39,500 -46.40 10,221 -46.04 n/a n/a n/a
2023-11-14 2023-09-30 13F BIOGEN COM Put 73,700 -9.01 18,942 -17.90 n/a n/a n/a
2023-08-14 2023-06-30 13F BIOGEN COM Put 81,000 53.12 23,073 56.87 n/a n/a n/a
2023-05-15 2023-03-31 13F BIOGEN COM Put 52,900 -69.56 14,708 -69.44 n/a n/a n/a
2023-02-14 2022-12-31 13F BIOGEN COM Put 173,800 5.85 48,129 9.78 n/a n/a n/a
2022-11-14 2022-09-30 13F BIOGEN COM Put 164,200 3.47 43,841 35.46 n/a n/a n/a
2022-08-15 2022-06-30 13F BIOGEN COM Put 158,700 -11.19 32,365 -14.00 n/a n/a n/a
2022-05-16 2022-03-31 13F BIOGEN COM Put 178,700 -37.01 37,634 -44.71 n/a n/a n/a
2022-02-14 2021-12-31 13F BIOGEN COM Put 283,700 -0.39 68,065 -15.55 n/a n/a n/a
2021-11-15 2021-09-30 13F BIOGEN COM Put 284,800 8.37 80,596 -11.43 n/a n/a n/a
2021-08-16 2021-06-30 13F BIOGEN COM Put 262,800 100.46 91,000 148.13 n/a n/a n/a
2021-05-17 2021-03-31 13F BIOGEN COM Put 131,100 50.86 36,675 72.36 n/a n/a n/a
2021-02-16 2020-12-31 13F BIOGEN COM Put 86,900 304.19 21,278 248.88 n/a n/a n/a
2020-11-16 2020-09-30 13F BIOGEN COM Put 21,500 -30.65 6,099 -26.46 n/a n/a n/a
2020-08-14 2020-06-30 13F BIOGEN COM Put 31,000 71.27 8,294 44.85 n/a n/a n/a
2020-05-14 2020-03-31 13F BIOGEN COM Put 18,100 293.48 5,726 319.49 n/a n/a n/a
2020-02-14 2019-12-31 13F BIOGEN COM Put 4,600 0.00 1,365 27.57 n/a n/a n/a
2019-11-14 2019-09-30 13F BIOGEN COM Put 4,600 0.00 1,070 -0.56 n/a n/a n/a
2019-08-15 2019-06-30 13F/A BIOGEN COM Put 4,600 0.00 1,076 -1.01 n/a n/a n/a
2019-05-14 2019-03-31 13F BIOGEN COM Put 4,600 0.00 1,087 -21.46 n/a n/a n/a
2019-02-15 2018-12-31 13F/A BIOGEN COM Put 4,600 0.00 1,384 -14.83 n/a n/a n/a
2019-02-14 2018-12-31 13F BIOGEN COM Put 4,600 1,384 n/a n/a n/a
2018-11-14 2018-09-30 13F BIOGEN COM Put 4,600 475.00 1,625 600.43 n/a n/a n/a
2018-08-14 2018-06-30 13F BIOGEN COM Put 800 -85.45 232 -84.92 n/a n/a n/a
2014-02-14 2013-12-31 13F BIOGEN IDEC COM Put 5,500 -80.70 1,538 -77.59 n/a n/a n/a
2013-11-14 2013-09-30 13F BIOGEN IDEC COM Put 28,500 -78.59 6,862 -76.04 n/a n/a n/a
2013-08-14 2013-06-30 13F BIOGEN IDEC COM Put 133,100 28,643 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.