Ultragenyx Pharmaceutical Inc.
US ˙ NasdaqGS ˙ US90400D1081

SecurityRARE / Ultragenyx Pharmaceutical Inc.
InstitutionD. E. Shaw & Co., Inc.
ManagerDE Shaw
Latest Disclosed Ownership1,261,018 shares
Latest Disclosed Value $ 26,418,327
D. E. Shaw & Co., Inc. ownership in RARE / Ultragenyx Pharmaceutical Inc.

On May 15, 2026 - D. E. Shaw & Co., Inc. filed a 13F-HR form disclosing ownership of 1,261,018 shares of Ultragenyx Pharmaceutical Inc. (US:RARE) valued at $26,418,327 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 344,763 shares of Ultragenyx Pharmaceutical Inc.. This represents a change in shares of 265.76% during the quarter. The current value of the position is $28,259,413 USD.

D. E. Shaw & Co., Inc. has a history of taking positions in derivatives of the underlying security (RARE) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD and put options representing 0 of underlying shares valued at $0 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.

RARE / Ultragenyx Pharmaceutical 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 ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 1,261,018 916,255 265.76 26,418 233.18 0.0117
2026-02-17 2025-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 344,763 107,123 45.08 7,930 10.93 0.0043
2025-11-14 2025-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 237,640 -303,161 -56.06 7,148 -63.65 0.0040
2025-08-14 2025-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 540,801 -15,616 -2.81 19,664 -2.40 0.0139
2025-05-15 2025-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 556,417 270,338 94.50 20,148 67.40 0.0179
2025-02-14 2024-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 286,079 24,485 9.36 12,035 -17.18 0.0088
2024-11-14 2024-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 261,594 58,152 28.58 14,532 73.80 0.0125
2024-08-14 2024-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 203,442 203,442 8,361 0.0078
2024-11-14 2023-12-31 13F/A-1 ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 0 -6,152 -100.00 0 -100.00
2024-02-14 2023-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 0 -6,152 0
2023-11-14 2023-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 6,152 -88,777 -93.52 219 -95.00 0.0002
2023-08-14 2023-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 94,929 -25,959 -21.47 4,379 -9.66 0.0045
2023-05-15 2023-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 120,888 -169,107 -58.31 4,848 -63.92 0.0052
2023-02-14 2022-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 289,995 -182,359 -38.61 13,435 -31.31 0.0148
2022-11-14 2022-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 472,354 112,837 31.39 19,560 -8.81 0.0234
2022-08-15 2022-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 359,517 -124,821 -25.77 21,449 -39.02 0.0251
2022-05-16 2022-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 484,338 -62,253 -11.39 35,173 -23.48 0.0329
2022-02-14 2021-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 546,591 70,884 14.90 45,963 7.13 0.0381
2021-11-15 2021-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 475,707 -290,390 -37.91 42,904 -41.27 0.0387
2021-08-16 2021-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 766,097 14,929 1.99 73,048 -14.59 0.0631
2021-05-17 2021-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 751,168 35,881 5.02 85,528 -13.62 0.0826
2021-02-16 2020-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 715,287 284,395 66.00 99,017 179.59 0.0885
2020-11-16 2020-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 430,892 93,728 27.80 35,415 34.29 0.0362
2020-08-14 2020-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 337,164 -61,310 -15.39 26,373 48.96 0.0314
2020-05-15 2020-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 398,474 84,306 26.83 17,705 31.95 0.0276
2020-02-14 2019-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 314,168 125,785 66.77 13,418 66.50 0.0153
2019-11-14 2019-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 188,383 54,777 41.00 8,059 -5.01 0.0099
2019-08-14 2019-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 133,606 -10,571 -7.33 8,484 -15.16 0.0106
2019-05-15 2019-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 144,177 -177,657 -55.20 10,000 -28.54 0.0129
2019-02-14 2018-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 321,834 316,434 5,859.89 13,993 3,296.36 0.0193
2018-11-14 2018-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 5,400 5,400 412 0.0005
2018-02-14 2017-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 0 -12,682 -100.00 0 -100.00
2017-11-14 2017-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 12,682 -54,193 -81.04 675 -83.75 0.0010
2017-08-14 2017-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 66,875 29,212 77.56 4,154 62.71 0.0069
2017-05-15 2017-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 37,663 37,663 2,553 0.0045
2016-05-16 2016-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 0 -58,488 -100.00 0 -100.00
2016-02-16 2015-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 58,488 47,790 446.72 6,561 536.99 0.0098
2015-11-16 2015-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 10,698 5,398 101.85 1,030 89.69 0.0015
2015-08-14 2015-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 5,300 -21,428 -80.17 543 -67.29 0.0008
2015-05-15 2015-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM 90400D108 26,728 26,728 1,660 0.0025
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
(%)
2021-11-15 2021-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-08-16 2021-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM Call 24,200 0.00 2,307 -16.26 n/a n/a n/a
2021-05-17 2021-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM Call 24,200 0.00 2,755 -17.76 n/a n/a n/a
2021-02-16 2020-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM Call 24,200 3,350 n/a n/a n/a
2016-05-16 2016-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2016-02-16 2015-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM Call 10,900 -54.96 1,223 -47.53 n/a n/a n/a
2015-11-16 2015-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM Call 24,200 2,331 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
(%)
2018-02-14 2017-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2017-11-14 2017-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM Put 10,000 0.00 533 -14.17 n/a n/a n/a
2017-08-14 2017-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM Put 10,000 621 n/a n/a n/a
2016-05-16 2016-03-31 13F ULTRAGENYX PHARMACEUTICAL IN COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2016-02-16 2015-12-31 13F ULTRAGENYX PHARMACEUTICAL IN COM Put 24,000 -29.41 2,692 -17.80 n/a n/a n/a
2015-11-16 2015-09-30 13F ULTRAGENYX PHARMACEUTICAL IN COM Put 34,000 240.00 3,275 219.82 n/a n/a n/a
2015-08-14 2015-06-30 13F ULTRAGENYX PHARMACEUTICAL IN COM Put 10,000 1,024 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.