JY
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Jeff Yass’s Spero Therapeutics SPRO Stock Holding History

Jeff Yass’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
Q2 		$76.5K Sell
34,600
-13,900
-29% -$36.4K ﹤0.01% 12654
2026
Q1 		$113K Buy
+48,500
New +$115K ﹤0.01% 12252
2025
Q4 		– Sell
-10,900
Closed -$20.5K – 13551
2025
Q3 		$20.5K Sell
10,900
-37,800
-78% -$83.1K ﹤0.01% 12048
2025
Q2 		$141K Buy
+48,700
New +$70K ﹤0.01% 11543
2023
Q1 		– Sell
-22,700
Closed -$39.3K – 13452
2022
Q4 		$39.3K Sell
22,700
-101,200
-82% -$189K ﹤0.01% 11521
2022
Q3 		$248K Buy
+123,900
New +$123K ﹤0.01% 10289
2022
Q1 		– Sell
-15,000
Closed -$240K – 13923
2021
Q4 		$240K Sell
15,000
-18,500
-55% -$294K ﹤0.01% 11039
2021
Q3 		$617K Buy
33,500
+9,200
+38% +$148K ﹤0.01% 8850
2021
Q2 		$339K Sell
24,300
-28,400
-54% -$397K ﹤0.01% 10506
2021
Q1 		$776K Buy
52,700
+13,300
+34% +$234K ﹤0.01% 8388
2020
Q4 		$764K Buy
39,400
+12,300
+45% +$192K ﹤0.01% 7329
2020
Q3 		$302K Buy
+27,100
New +$321K ﹤0.01% 8693

Other funds holding SPRO

GP
GSK plc London $602M AUM
P
Pfizer New York $170M AUM 191.09% 1-Year Est. Return
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
Renaissance Technologies
Renaissance Technologies New York $72.6B AUM 54.88% 1-Year Est. Return
AI
Alphabet Inc Mountain View, California $99.1B AUM 124.46% 1-Year Est. Return
BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return
Raymond James Financial
Raymond James Financial St Petersburg, Florida $369B AUM 28.27% 1-Year Est. Return
Two Sigma Investments
Two Sigma Investments New York $138B AUM 41.87% 1-Year Est. Return
Arrowstreet Capital
Arrowstreet Capital Boston, Massachusetts $225B AUM 49.49% 1-Year Est. Return

Jeff Yass's SPRO Position: Q2 2026 in Review

Jeff Yass increased its Spero Therapeutics (SPRO) stake by 128% in Q2 2026, buying an estimated $1.11M and bringing the position to 759,290 shares worth $1.68M. The position accounts for ﹤0.01% of the portfolio, ranked #6880.

Jeff Yass first reported a position in SPRO in Q3 2019 and has held it in 23 quarters since. 60 funds tracked by Wall St. Rank hold SPRO as of Q2 2026.

  • Jeff Yass held 759,290 shares of Spero Therapeutics worth $1.68M as of Q2 2026.
  • Jeff Yass bought 426,175 Spero Therapeutics shares in Q2 2026, an estimated $1.11M.
  • Spero Therapeutics made up ﹤0.01% of Jeff Yass's portfolio in Q2 2026, its #6880 holding.
  • Jeff Yass first reported a position in Spero Therapeutics in Q3 2019 and has held it in 23 quarters since.
  • 60 funds tracked by Wall St. Rank held Spero Therapeutics as of Q2 2026.

Based on Susquehanna International Group's 13F filing for Q2 2026, filed 14 Aug 2026.