Ken Griffin
SPRO icon

Ken Griffin’s Spero Therapeutics SPRO Stock Holding History

Ken Griffin’s Portfolio SPRO Stock Details SPRO Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q1 		$881K Sell
376,458
-21,406
-5% -$50.8K ﹤0.01% 7955
2025
Q4 		$927K Buy
+397,864
New +$924K ﹤0.01% 7569
2025
Q3 		– Sell
-103,786
Closed -$228K – 14018
2025
Q2 		$301K Buy
103,786
+42,470
+69% +$61.1K ﹤0.01% 9819
2025
Q1 		$44.1K Sell
61,316
-111,556
-65% -$94.2K ﹤0.01% 12436
2024
Q4 		$178K Buy
172,872
+91,447
+112% +$109K ﹤0.01% 10627
2024
Q3 		$109K Sell
81,425
-230,609
-74% -$309K ﹤0.01% 10997
2024
Q2 		$406K Buy
+312,034
New +$471K ﹤0.01% 8484
2024
Q1 		– Sell
-32,274
Closed -$47.4K – 15387
2023
Q4 		$47.4K Buy
+32,274
New +$38.5K ﹤0.01% 11834
2023
Q3 		– Sell
-14,956
Closed -$21.7K – 15063
2023
Q2 		$21.7K Buy
+14,956
New +$25.6K ﹤0.01% 12664
2022
Q3 		– Sell
-108,351
Closed -$80K – 13553
2022
Q2 		$80K Buy
108,351
+97,554
+904% +$284K ﹤0.01% 11596
2022
Q1 		$94K Buy
+10,797
New +$111K ﹤0.01% 12347
2021
Q3 		– Sell
-11,812
Closed -$190K – 14600
2021
Q2 		$165K Sell
11,812
-8,268
-41% -$116K ﹤0.01% 12397
2021
Q1 		$296K Sell
20,080
-12,558
-38% -$221K ﹤0.01% 10889
2020
Q4 		$633K Buy
32,638
+11,328
+53% +$177K ﹤0.01% 7708
2020
Q3 		$238K Buy
+21,310
New +$252K ﹤0.01% 8540

Other funds holding SPRO

GP
GSK plc London $599M AUM
P
Pfizer New York $239M AUM 232.47% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
Renaissance Technologies
Renaissance Technologies New York $63.9B AUM 45.56% 1-Year Est. Return
AI
Alphabet Inc Mountain View, California $99.1B AUM 124.46% 1-Year Est. Return
Two Sigma Investments
Two Sigma Investments New York $124B AUM 33.93% 1-Year Est. Return
AFM
Anson Funds Management Dallas, Texas $2.29B AUM 370.1% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return
BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
Susquehanna International Group
Susquehanna International Group Bala Cynwyd, Pennsylvania $893B AUM 36.07% 1-Year Est. Return

Ken Griffin's SPRO Position: Q1 2026 in Review

Ken Griffin reduced its Spero Therapeutics (SPRO) stake by 5.4% in Q1 2026, selling an estimated $50.8K and leaving 376,458 shares worth $881K. The position accounts for ﹤0.01% of the portfolio, ranked #7955.

Ken Griffin first reported a position in SPRO in Q3 2020 and has held it in 15 quarters since. The position peaked at $927K in Q4 2025. 50 funds tracked by Wall St. Rank hold SPRO as of Q1 2026.

  • Ken Griffin held 376,458 shares of Spero Therapeutics worth $881K as of Q1 2026.
  • Ken Griffin sold 21,406 Spero Therapeutics shares in Q1 2026, an estimated $50.8K.
  • Spero Therapeutics made up ﹤0.01% of Ken Griffin's portfolio in Q1 2026, its #7955 holding.
  • Ken Griffin first reported a position in Spero Therapeutics in Q3 2020 and has held it in 15 quarters since.
  • Ken Griffin's Spero Therapeutics position peaked at $927K in Q4 2025.
  • 50 funds tracked by Wall St. Rank held Spero Therapeutics as of Q1 2026.

Based on Citadel Advisors's 13F filing for Q1 2026, filed 15 May 2026.