Jane Street’s Spero Therapeutics SPRO Stock Holding History

Jane Street’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	$349K	Buy	158,097 +51,752	+49%	+$135K	﹤0.01%	8867
2026 Q1	$249K	Sell	106,345 -51,999	-33%	-$123K	﹤0.01%	9639
2025 Q4	$369K	Buy	158,344 +115,356	+268%	+$268K	﹤0.01%	8376
2025 Q3	$80.8K	Buy	+42,988	New	+$94.5K	﹤0.01%	10224
2025 Q1	–	Sell	-52,869	Closed	-$54.5K	–	10542
2024 Q4	$54.5K	Buy	+52,869	New	+$62.9K	﹤0.01%	8945
2022 Q4	–	Sell	-15,496	Closed	-$31K	–	10093
2022 Q3	$31K	Buy	+15,496	New	+$15.4K	﹤0.01%	9084
2022 Q2	–	Sell	-15,622	Closed	-$136K	–	10800
2022 Q1	$136K	Buy	+15,622	New	+$160K	﹤0.01%	9295
2021 Q2	–	Sell	-11,496	Closed	-$169K	–	10368
2021 Q1	$169K	Buy	+11,496	New	+$202K	﹤0.01%	8381

Other funds holding SPRO

GSK plc London $602M AUM

Pfizer New York $170M AUM 191.09% 1-Year Est. Return

Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM

Renaissance Technologies New York $72.6B AUM 54.88% 1-Year Est. Return

Alphabet Inc Mountain View, California $99.1B AUM 124.46% 1-Year Est. Return

Susquehanna International Group Bala Cynwyd, Pennsylvania $1.28T AUM 58.89% 1-Year Est. Return

BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return

Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return

Raymond James Financial St Petersburg, Florida $369B AUM 28.27% 1-Year Est. Return

Two Sigma Investments New York $138B AUM 41.87% 1-Year Est. Return

Jane Street's SPRO Position: Q2 2026 in Review

Jane Street increased its Spero Therapeutics (SPRO) stake by 49% in Q2 2026, buying an estimated $135K and bringing the position to 158,097 shares worth $349K. The position accounts for ﹤0.01% of the portfolio, ranked #8867.

Jane Street first reported a position in SPRO in Q1 2021 and has held it in 8 quarters since. The position peaked at $369K in Q4 2025. 60 funds tracked by Wall St. Rank hold SPRO as of Q2 2026.

Jane Street held 158,097 shares of Spero Therapeutics worth $349K as of Q2 2026.
Jane Street bought 51,752 Spero Therapeutics shares in Q2 2026, an estimated $135K.
Spero Therapeutics made up ﹤0.01% of Jane Street's portfolio in Q2 2026, its #8867 holding.
Jane Street first reported a position in Spero Therapeutics in Q1 2021 and has held it in 8 quarters since.
Jane Street's Spero Therapeutics position peaked at $369K in Q4 2025.
60 funds tracked by Wall St. Rank held Spero Therapeutics as of Q2 2026.

Based on Jane Street's 13F filing for Q2 2026, filed 14 Aug 2026.