Hudson Bay Capital Management
RARE icon

Hudson Bay Capital Management’s Ultragenyx Pharmaceutical RARE Stock Holding History

Hudson Bay Capital Management’s Portfolio RARE Stock Details RARE Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2025
Q4 		– Sell
-265,000
Closed -$8.71M – 1473
2025
Q3 		$7.97M Buy
265,000
+6,319
+2% +$190K 0.03% 410
2025
Q2 		$9.41M Sell
258,681
-121,519
-32% -$4.38M 0.03% 368
2025
Q1 		$13.8M Buy
380,200
+2,700
+0.7% +$112K 0.04% 328
2024
Q4 		$15.9M Buy
377,500
+182,500
+94% +$9.05M 0.06% 275
2024
Q3 		$10.8M Sell
195,000
-220,000
-53% -$11.2M 0.04% 269
2024
Q2 		$17.1M Buy
415,000
+109,900
+36% +$4.69M 0.08% 153
2024
Q1 		$14.2M Sell
305,100
-184,900
-38% -$8.72M 0.08% 137
2023
Q4 		$23.4M Sell
490,000
-244,272
-33% -$9.47M 0.15% 91
2023
Q3 		$26.2M Buy
734,272
+232,500
+46% +$9.21M 0.21% 76
2023
Q2 		$23.1M Sell
501,772
-70,000
-12% -$3.25M 0.17% 104
2023
Q1 		$22.9M Buy
571,772
+5,772
+1% +$248K 0.19% 95
2022
Q4 		$26.2M Buy
566,000
+226,000
+66% +$8.89M 0.27% 79
2022
Q3 		$14.1M Buy
340,000
+249,000
+274% +$12.8M 0.12% 109
2022
Q2 		$5.43M Buy
+91,000
New +$5.6M 0.04% 395
2020
Q4 		– Sell
-30,000
Closed -$2.47M – 684
2020
Q3 		$2.47M Sell
30,000
-105,000
-78% -$8.7M 0.04% 333
2020
Q2 		$10.6M Sell
135,000
-98,706
-42% -$6.53M 0.18% 93
2020
Q1 		$10.4M Sell
233,706
-56,294
-19% -$2.92M 0.26% 71
2019
Q4 		$12.4M Buy
290,000
+135,000
+87% +$5.57M 0.28% 63
2019
Q3 		$6.63M Buy
155,000
+45,000
+41% +$2.44M 0.18% 112
2019
Q2 		$6.99M Hold
110,000
– – 0.16% 135
2019
Q1 		$7.63M Buy
110,000
+10,000
+10% +$571K 0.1% 201
2018
Q4 		$4.35M Buy
+100,000
New +$5.47M 0.06% 336
2018
Q2 		– Sell
-120,000
Closed -$6.12M – 945
2018
Q1 		$6.12M Buy
120,000
+20,000
+20% +$1.01M 0.13% 183
2017
Q4 		$4.64M Buy
+100,000
New +$4.9M 0.1% 177

Other funds holding RARE

BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
AQR Capital Management
AQR Capital Management Greenwich, Connecticut $218B AUM 29.41% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
RI
RTW Investments New York $10B AUM 135.35% 1-Year Est. Return
Sands Capital Management
Sands Capital Management Arlington, Virginia $25.5B AUM 26.46% 1-Year Est. Return
SI
Sofinnova Investments Menlo Park, California $2.63B AUM 117.41% 1-Year Est. Return
Wellington Management Group
Wellington Management Group Boston, Massachusetts $535B AUM 26.23% 1-Year Est. Return
BG
Bellevue Group Kuesnacht, Switzerland $4.2B AUM 54.85% 1-Year Est. Return

Hudson Bay Capital Management's RARE Position: Q4 2025 in Review

Hudson Bay Capital Management sold out of Ultragenyx Pharmaceutical (RARE) in Q4 2025, closing a stake of 265,000 shares — an estimated $8.71M sold.

Hudson Bay Capital Management first reported a position in RARE in Q4 2017 and held it in 24 quarters. The position peaked at $26.2M in Q4 2022. 287 funds tracked by Wall St. Rank hold RARE as of Q4 2025.

  • Hudson Bay Capital Management reported no remaining Ultragenyx Pharmaceutical position as of Q4 2025 after selling out during the quarter.
  • Hudson Bay Capital Management sold 265,000 Ultragenyx Pharmaceutical shares in Q4 2025, an estimated $8.71M.
  • Hudson Bay Capital Management first reported a position in Ultragenyx Pharmaceutical in Q4 2017 and held it in 24 quarters.
  • Hudson Bay Capital Management's Ultragenyx Pharmaceutical position peaked at $26.2M in Q4 2022.
  • 287 funds tracked by Wall St. Rank held Ultragenyx Pharmaceutical as of Q4 2025.

Based on Hudson Bay Capital Management's 13F filing for Q4 2025, filed 13 Feb 2026.