Stock

SPRO

SPERO THERAPEUTICS, INC.

Latest close $2.584 of 27 marquee funds currently hold1 CUSIP mapped

Current holders

27 funds tracked

Ever held

Current + past

New this quarter

Exited this quarter

Marquee-fund ownership over time

Aug 9, 2024Feb 14, 2025Feb 17, 2026May 15, 2026

Now

This quarter's activity

New positions opened

None.

Positions exited

Millennium Management
Q2 2026 · +19%
EXIT

Current holders

Sorted by tenure (longest first)

Fund	First disclosed	Held	Entry price	Latest close	Return on entry
Renaissance Technologies	Q3 2024(8Q snapshot)	7Q	$1.28	$2.58	+102%
Citadel Advisors re-entered	Q3 2024(8Q snapshot)	7Q	$1.22	$2.58	+111%
Two Sigma Investments	Q4 2025(8Q snapshot)	2Q	$2.41	$2.58	+7%
Point72 Asset Management	Q1 2026(8Q snapshot)	1Q	$2.35	$2.58	+10%

“Return on entry” is the price-only move from the fund's first disclosure to today — it ignores any adds, trims, or dividends. A fund that built its position over multiple quarters has a true cost basis somewhere between entry price and latest close; this figure is the upper bound.

Past holders

Funds that exited at some point

Fund	Last entry	Exited	Entry → Exit	Return
Millennium Management 2× in & out	Q1 2026	Q2 2026	→ $2.79	+19%

Insider activity

Form 4 — officers, directors, 10%+ owners

Filed within two business days of each transaction by anyone with material insider status at Spero Therapeutics, Inc.. Pair with the holders table above as a sanity check: heavy insider buying alongside marquee-fund accumulation is the strongest accumulation signal; heavy insider selling alongside fund exits is the strongest distribution signal.

Filings · last 30d

Filings · last 90d

Total on file

189

Recent SEC buffer

Most recent

May 6, 2026

30d / 90d windows measured from May 6, 2026 — the most recent Form 4 on file — not from today.

Showing 15 of 189 recent Form 4 filings. Browse all on EDGAR ↗

Fundamentals

XBRL · SPERO THERAPEUTICS, INC.

Annual figures sourced directly from SPERO THERAPEUTICS, INC.'s 10-K / 10-Q filings via SEC EDGAR XBRL. Latest fiscal year and the year-over-year change, with up to ten years of history.

Revenue

$66.8M

FY2025+39% YoY

Net income

$8.57M

FY2025+113% YoY

EPS (diluted)

$0.1500

FY2025+112% YoY

Free cash flow(?)

-$12.62M

FY2025+46% YoY

Recent SEC filings

10-K · 10-Q · 8-K · 13D/G · proxy

The most recent material filings for Spero Therapeutics, Inc. — earnings, material events, ownership disclosures, proxy statements. Form 4 insider activity is shown in the panel above.

Trade history

Every open→close lifecycle across tracked funds

Fund	Open date	Close date	Open price	Close price / current	Return
Citadel Advisors	Q1 2026	open	$2.35	$2.58	+10%
Millennium Management	Q1 2026	Q2 2026	$2.35	$2.79	+19%
Point72 Asset Management	Q1 2026	open	$2.35	$2.58	+10%
Two Sigma Investments	Q4 2025	open	$2.41	$2.58	+7%
Citadel Advisors	Q3 2024	Q4 2025	$1.22	$2.41	+98%
Millennium Management	Q3 2024	Q1 2025	$1.22	$0.81	-33%
Renaissance Technologies	Q3 2024	open	$1.28	$2.58	+102%

Caveats

Covers only the 27 marquee funds tracked here, not the full institutional universe. A “0 holders” reading does not mean unowned.
Heavy funds (Renaissance Technologies, Citadel Advisors, Soros Fund Management, Two Sigma Investments, D.E. Shaw, AQR Capital Management, Millennium Management, Point72 Asset Management) use 8-quarter snapshots, so their pre-2024 history is missing.
“Current” reflects each fund's most recent 13F — filings lag the actual trade by up to 45 days; positions shown may have changed since.
Cost = price at the entry filing date. Re-entered positions show the most recent open lot.
Options, ADRs, and unmapped CUSIPs are excluded from the follower-backtest pipeline that produces these snapshots, so certain holding types won't appear here.