SIMPLEX TRADING, LLC

Position in SPRO — Spero Therapeutics, Inc.

CIK 1488542 CHICAGO, IL

Position in SPRO

as of Jun 30, 2026 · filed Aug 12, 2026 Compact

Position Value

$135,499

+$64,588 QoQ

Shares Held

61,312

+102.3% QoQ

Ownership

0.105%

of shares outstanding

% of Portfolio

0.00%

of 13F equity value

Holder Rank

#26

of 59 holders

Holding Since

Jun 2020

16 quarters on record

Voting authority Sole 100% Shared 0% None 0%

Healthcare · as of Jun 30, 2026

SIMPLEX TRADING, LLC holds $83,352,766 across 183 Biotechnology names. SPRO ranks #76 (0.2% of the industry book) .

#	Ticker	Company	Shares	Value (USD)
1	MRNA	Moderna, Inc.	154,558	$10,823,696
2	QURE	uniQure N.V.	110,219	$5,076,687
3	ERAS	Erasca, Inc.	276,988	$5,074,420
4	AXSM	Axsome Therapeutics, Inc.	19,643	$4,808,017
5	BBIO	BridgeBio Pharma, Inc.	55,535	$4,136,246
6	ALNY	Alnylam Pharmaceuticals, Inc.	11,567	$3,482,014
7	ARWR	Arrowhead Pharmaceuticals, Inc.	29,002	$2,363,953
8	SLS	SELLAS Life Sciences Group, Inc.	154,099	$2,274,501

16 filing rows on record

Report Date	Value (USD)	Shares	Change	Type	Discretion	Filed
2026-06-30	$135,499	61,312	+102.3%	Shares	Sole	2026-08-12
2026-03-31	$70,911	30,304	-15.1%	Shares	Sole	2026-05-14
2025-12-31	$83,148	35,686	+368.4%	Shares	Sole	2026-02-11
2025-09-30	$14,321	7,618	-74.9%	Shares	Sole	2025-11-12
2025-06-30	$87,933	30,322	+494.8%	Shares	Sole	2025-08-05
2025-03-31	$3	5,098	-0.2%	Shares	Sole	2025-05-12
2024-12-31	$5,263	5,110	+454.8%	Shares	Sole	2025-02-11
2024-09-30	$1	921	-59.6%	Shares	Sole	2024-11-08
2023-06-30	$3	2,281	-75.2%	Shares	Sole	2023-08-04
2022-12-31	$15,926	9,206	+820.6%	Shares	Sole	2023-02-02
2022-09-30	$2,000	1,000	-89.2%	Shares	Sole	2022-11-04
2022-06-30	$6,891	9,300	+46.5%	Shares	Sole	2022-08-03
2022-03-31	$55,210	6,346	+1151.7%	Shares	Sole	2022-05-02
2021-06-30	$7,077	507	-16.3%	Shares	Sole	2021-08-12
2020-12-31	$11,750	606	+203.0%	Shares	Sole	2021-02-02
2020-06-30	$2,706	200	—	Shares	Sole	2020-07-13
No filing history on record for this holder in this stock.