P
SPRO icon

Pfizer’s Spero Therapeutics SPRO Stock Holding History

Pfizer’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 		$5.34M Hold
2,362,348
– – 3.13% 8
2026
Q1 		$5.5M Hold
2,362,348
– – 2.31% 9
2025
Q4 		$5.5M Hold
2,362,348
– – 2.33% 11
2025
Q3 		$4.44M Hold
2,362,348
– – 1.02% 13
2025
Q2 		$6.85M Hold
2,362,348
– – 1.19% 10
2025
Q1 		$1.7M Hold
2,362,348
– – 0.34% 14
2024
Q4 		$2.43M Buy
+2,362,348
New +$2.81M 0.09% 17

Other funds holding SPRO

GP
GSK plc London $602M AUM
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
Susquehanna International Group
Susquehanna International Group Bala Cynwyd, Pennsylvania $1.28T AUM 58.89% 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

Pfizer's SPRO Position: Q2 2026 in Review

Pfizer held its Spero Therapeutics (SPRO) position steady in Q2 2026 at 2,362,348 shares worth $5.34M. The position accounts for 3.13% of the portfolio, ranked #8.

Pfizer first reported a position in SPRO in Q4 2024 and has held it in 7 quarters since. The position peaked at $6.85M in Q2 2025. 60 funds tracked by Wall St. Rank hold SPRO as of Q2 2026.

  • Pfizer held 2,362,348 shares of Spero Therapeutics worth $5.34M as of Q2 2026.
  • Pfizer left its Spero Therapeutics share count unchanged in Q2 2026.
  • Spero Therapeutics made up 3.13% of Pfizer's portfolio in Q2 2026, its #8 holding.
  • Pfizer first reported a position in Spero Therapeutics in Q4 2024 and has held it in 7 quarters since.
  • Pfizer's Spero Therapeutics position peaked at $6.85M in Q2 2025.
  • 60 funds tracked by Wall St. Rank held Spero Therapeutics as of Q2 2026.

Based on Pfizer's 13F filing for Q2 2026, filed 13 Aug 2026.