Biogen Inc.
US ˙ NasdaqGS ˙ US09062X1037

SecurityBIIB / Biogen Inc.
InstitutionPrivate Advisor Group, LLC
Latest Disclosed Ownership4,649 shares
Latest Disclosed Value $ 852,301
Private Advisor Group, LLC ownership in BIIB / Biogen Inc.

On April 24, 2026 - Private Advisor Group, LLC filed a 13F-HR form disclosing ownership of 4,649 shares of Biogen Inc. (US:BIIB) valued at $852,301 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 6,113 shares of Biogen Inc.. This represents a change in shares of -23.95% during the quarter. The current value of the position is $911,018 USD.

Private Advisor Group, LLC has a history of taking positions in derivatives of the underlying security (BIIB) 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.

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)
2026-04-24 2026-03-31 13F BIOGEN COM 09062X103 4,649 -1,464 -23.95 852 -20.74 0.0038
2026-02-17 2025-12-31 13F BIOGEN COM 09062X103 6,113 1,646 36.85 1,076 72.00 0.0048
2025-11-13 2025-09-30 13F BIOGEN COM 09062X103 4,467 229 5.40 626 17.48 0.0031
2025-08-11 2025-06-30 13F BIOGEN COM 09062X103 4,238 -318 -6.98 532 -14.61 0.0029
2025-05-05 2025-03-31 13F BIOGEN COM 09062X103 4,556 -1,341 -22.74 623 -30.85 0.0038
2025-02-03 2024-12-31 13F BIOGEN COM 09062X103 5,897 -3,748 -38.86 902 -51.79 0.0051
2024-10-22 2024-09-30 13F BIOGEN COM 09062X103 9,645 924 10.60 1,870 -7.52 0.0116
2024-08-05 2024-06-30 13F BIOGEN COM 09062X103 8,721 3,888 80.45 2,022 93.95 0.0136
2024-04-30 2024-03-31 13F BIOGEN COM 09062X103 4,833 224 4.86 1,042 -12.58 0.0075
2024-02-06 2023-12-31 13F BIOGEN COM 09062X103 4,609 -20 -0.43 1,193 0.25 0.0093
2023-11-03 2023-09-30 13F BIOGEN COM 09062X103 4,629 97 2.14 1,190 -5.86 0.0106
2023-08-10 2023-06-30 13F BIOGEN COM 09062X103 4,532 11 0.24 1,263 0.56 0.0110
2023-05-10 2023-03-31 13F BIOGEN COM 09062X103 4,521 -1,524 -25.21 1,257 67.47 0.0120
2023-01-18 2022-12-31 13F BIOGEN COM 09062X103 6,045 1,787 41.97 751 -34.04 0.0378
2022-10-14 2022-09-30 13F BIOGEN COM 09062X103 4,258 -2,238 -34.45 1,137 -14.19 0.0131
2022-07-13 2022-06-30 13F BIOGEN COM 09062X103 6,496 789 13.83 1,325 10.23 0.0118
2022-05-12 2022-03-31 13F/A-1 BIOGEN COM 09062X103 5,707 -440 -7.16 1,202 -18.51 0.0092
2022-05-10 2022-03-31 13F BIOGEN COM 09062X103 6,147 0 1,475 0.0111
2022-02-10 2021-12-31 13F BIOGEN COM 09062X103 6,147 -36,314 -85.52 1,475 -87.73 0.0111
2021-10-14 2021-09-30 13F BIOGEN COM 09062X103 42,461 34,676 445.42 12,017 345.73 0.0764
2021-08-12 2021-06-30 13F BIOGEN COM 09062X103 7,785 104 1.35 2,696 25.45 0.0235
2021-04-22 2021-03-31 13F BIOGEN COM 09062X103 7,681 1,364 21.59 2,149 38.91 0.0205
2021-04-01 2020-12-31 13F BIOGEN COM 09062X103 6,317 -291 -4.40 1,547 -15.56 0.0161
2020-11-02 2020-09-30 13F BIOGEN COM 09062X103 6,608 -717 -9.79 1,832 -6.53 0.0238
2020-08-17 2020-06-30 13F BIOGEN COM 09062X103 7,325 1,020 16.18 1,960 -1.75 0.0272
2020-05-12 2020-03-31 13F BIOGEN COM 09062X103 6,305 372 6.27 1,995 13.29 0.0366
2020-02-10 2019-12-31 13F BIOGEN COM 09062X103 5,933 -4,234 -41.64 1,761 -33.30 0.0274
2019-11-13 2019-09-30 13F BIOGEN COM 09062X103 10,167 4,908 93.33 2,640 114.63 0.0411
2019-08-14 2019-06-30 13F BIOGEN COM 09062X103 5,259 153 3.00 1,230 1.49 0.0222
2019-05-13 2019-03-31 13F BIOGEN COM 09062X103 5,106 103 2.06 1,212 -19.36 0.0239
2019-02-08 2018-12-31 13F BIOGEN COM 09062X103 5,003 -2,233 -30.86 1,503 -41.22 0.0362
2018-11-01 2018-09-30 13F BIOGEN COM 09062X103 7,236 -15,190 -67.73 2,557 -60.83 0.0524
2018-08-09 2018-06-30 13F BIOGEN COM 09062X103 22,426 20,093 861.25 6,528 916.82 0.1071
2018-05-09 2018-03-31 13F BIOGEN COM 09062X103 2,333 -2,783 -54.40 642 -61.72 0.0251
2018-02-07 2017-12-31 13F BIOGEN COM 09062X103 5,116 -1,711 -25.06 1,677 -24.93 0.0708
2017-11-13 2017-09-30 13F BIOGEN COM 09062X103 6,827 1,368 25.06 2,234 49.63 0.0552
2017-08-10 2017-06-30 13F BIOGEN COM 09062X103 5,459 -570 -9.45 1,493 -8.52 0.0404
2017-05-10 2017-03-31 13F BIOGEN COM 09062X103 6,029 220 3.79 1,632 -2.04 0.0456
2017-02-09 2016-12-31 13F BIOGEN COM 09062X103 5,809 539 10.23 1,666 1.46 0.0546
2016-11-10 2016-09-30 13F BIOGEN COM 09062X103 5,270 -132 -2.44 1,642 22.81 0.0670
2016-08-09 2016-06-30 13F BIOGEN COM 09062X103 5,402 1,562 40.68 1,337 66.71 0.0540
2016-05-13 2016-03-31 13F BIOGEN COM 09062X103 3,840 569 17.40 802 -19.96 0.0388
2016-02-09 2015-12-31 13F BIOGEN COM 09062X103 3,271 603 22.60 1,002 28.63 0.0480
2015-11-13 2015-09-30 13F BIOGEN COM 09062X103 2,668 173 6.93 779 -22.72 0.0428
2015-08-13 2015-06-30 13F BIOGEN COM 09062X103 2,495 143 6.08 1,008 1.51 0.0478
2015-05-13 2015-03-31 13F BIOGEN COM 09062X103 2,352 85 3.75 993 28.96 0.0572
2015-02-17 2014-12-31 13F BIOGEN IDEC COM 09062X103 2,267 552 32.19 770 35.80 0.0496
2014-11-12 2014-09-30 13F BIOGEN IDEC COM 09062X103 1,715 396 30.02 567 36.30 0.0392
2014-08-08 2014-06-30 13F BIOGEN IDEC COM 09062X103 1,319 69 5.52 416 8.90 0.0358
2014-05-15 2014-03-31 13F BIOGEN IDEC COM 09062X103 1,250 326 35.28 382 48.06 0.0403
2014-02-13 2013-12-31 13F BIOGEN IDEC COM 09062X103 924 924 258 0.0288
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
(%)
2024-02-06 2023-12-31 13F BIOGEN COM Put 0 -100.00 0 n/a n/a n/a
2023-11-03 2023-09-30 13F BIOGEN COM Put 300 1 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.