SPRO

Spero Therapeutics Inc Cross-source read$1.13 0.89%
Health CareCUSIP 84833T103· EOD Sep 11, 2026

Among active 13F managers last quarter, 5 opened and 5 added, while 1 reduced; the largest holder to move was Renaissance Technologies LLC (−7.0%). Over the last 180 days, 1 insider sold and none bought, a net -$63K in open-market trades.

Tracked 13F holders
43
11 in Q2 2026 filings
13F value (tracked)
$24.2M
Smart-money readMixed
Net sellingNet buying
Funds · active managers, latest 13F
10 adding · 1 trimming
Insiders · Form 4 open-market, 180d
0 buying · 1 selling · -$63K
US House · STOCK Act, 180d
0 buying · 0 selling

The legs disagree, or only one of them leans.

Price & smart-money activity

$1.13 0.89%5Y -93.9%
$0.53$5.64$10.76$15.87$20.9820212022202320242025202623546151341514381291145557658556865858296929872610119791155
Hover for who · click for detailEnd-of-day closing prices52w $1.12 – $2.98

Who owns SPRO?

43 tracked 13F filers · ranked by shares held

43 tracked 13F filers disclose a position in SPRO as of the latest SEC 13F filings, a combined $24.2M in reported value. Holders and values reflect the 13F filers Arkolith currently tracks, not the entire institutional universe. Counts and totals are a floor, not the full institutional ownership.

#FundSharesPosition valueLast moveAs ofHistory
1Pfizer Inc2.4M
$5.3M
Held
Q2 2026
2Vanguard Capital Management LLC2.0M
$4.5M
+13%
Added · +236K sh
Q2 2026
3Renaissance Technologies LLC1.2M
$2.8M
−7.0%
Reduced · −90K sh
Q1 2026
4Alphabet Inc.890K
$2.0M
Held
Q2 2026
5Two Sigma Investments, LP886K
$2.1M
+138%
Added · +513K sh
Q1 2026
6BlackRock, Inc.594K
$1.3M
+37%
Added · +161K sh
Q2 2026
7Geode Capital Management, LLC566K
$1.3M
+8.9%
Added · +46K sh
Q2 2026
8Susquehanna International Group, LLP333K
$779K
+13%
Added · +39K sh
Q1 2026
9Vanguard Fiduciary Trust Co288K
$636K
+8.9%
Added · +24K sh
Q2 2026
10State Street Corp215K
$475K
Held
Q2 2026
11Squarepoint Ops LLC194K
$455K
+63%
Added · +75K sh
Q1 2026
12Marshall Wace, LLP157K
$368K
New
+157K sh
Q1 2026
13Northern Trust Corp121K
$283K
Held
Q1 2026
14Bridgeway Capital Management, LLC115K
$254K
Held
Q2 2026
15Jane Street Group, LLC106K
$249K
−33%
Reduced · −52K sh
Q1 2026
16Point72 Asset Management, L.P.104K
$231K
+75%
Added · +45K sh
Q2 2026
17Ionic Capital Management LLC103K
$227K
−48%
Reduced · −93K sh
Q2 2026
18Federation des caisses Desjardins du Quebec92K
$202K
New
+92K sh
Q2 2026
19Shay Capital LLC72K
$160K
+2.9%
Added · +2K sh
Q2 2026
20Axxcess Wealth Management, LLC33K
$72K
Added
Added · +33K sh
Q2 2026
21Capital Asset Advisory Services LLC33K
$72K
Held
Q2 2026
22DLK Investment Management, LLC31K
$41K
New
+31K sh
Q2 2026
23Simplex Trading, LLC30K
$71K
−15%
Reduced · −5K sh
Q1 2026
24Dimensional Fund Advisors LP30K
$69K
Held
Q1 2026
25Charles Schwab Investment Management Inc29K
$67K
Held
Q1 2026

Holders and values reflect the 13F filers Arkolith currently tracks, not the entire institutional universe. Counts and totals are a floor, not the full institutional ownership.

Is SPRO being bought or sold by institutions?

Last quarter, 5 funds opened a new position in SPRO and 5 added to an existing one, while 1 reduced. Based on 13F filings from active, signal-eligible managers (passive index funds and other mechanical holders are excluded from this count).

Opened
5
funds took a first position
Added
5
added to an existing position
Reduced
1
reduced, still holding
Biggest moves · ranked by size of the change, positions above a floor

Funds that own SPRO also own

CompanyCo-held byTheir position there
Nvidia CorpNVDA14 funds$6.8B
Alphabet Inc-CL AGOOGL14 funds$3.6B
Microsoft CorpMSFT14 funds$3.4B
Meta Platforms Inc-Class AMETA14 funds$1.9B
Visa Inc-Class A SharesV14 funds$1.2B
Broadcom IncAVGO13 funds$2.7B
Advanced Micro DevicesAMD13 funds$2.2B
Chevron CorpCVX13 funds$1.9B
Airbnb Inc-Class AABNB13 funds$1.1B
Oracle CorpORCL13 funds$759.6M
Teradyne IncTER13 funds$685.2M
Netflix IncNFLX13 funds$598.3M

Ranked by how many of SPRO's tracked holders also hold each name. The last column is those co-holders' combined reported position in that name, not in SPRO.

Insider activity (Form 4)

Full insider page →
Sells · 180d
$63K
1 insider
Net · 180d
-$63K
1 open-market transaction
DateInsiderRoleActionSharesValue
May 4, 2026Rajavelu EstherSee RemarksSell (S)25K$63K
Feb 6, 2026Keutzer TimothyChief Operating OfficerSell (S)19K$44K
Feb 6, 2026Rajavelu EstherSee RemarksSell (S)
2 lots, same day
88K$207K
Feb 4, 2026Keutzer TimothyChief Operating OfficerSell (S)3K$8K
Feb 3, 2026Keutzer TimothyChief Operating OfficerSell (S)24K$52K
Feb 2, 2026Rajavelu EstherSee RemarksSell (S)18K$41K
Feb 2, 2026Keutzer TimothyChief Operating OfficerSell (S)19K$42K
Nov 7, 2025Rajavelu EstherSee RemarksSell (S)40K$95K
Aug 28, 2025Keutzer TimothyChief Operating OfficerSell (S)2K$3K
Aug 28, 2025Mahadevia AnkitDirectorSell (S)7K$13K
Feb 5, 2025Mahadevia AnkitDirectorSell (S)
2 lots, same day
69K$54K
Feb 5, 2025Shukla SathCEO & PresidentSell (S)
3 lots, same day
155K$121K

One row per insider, day and transaction code; shares and value are summed across the lots. Every lot is on the full insider page and in the filing.

Do institutions, insiders and Congress agree?

Mixed signals

Where institutional funds (13F), corporate insiders (Form 4) and US House members (STOCK Act) are buying or selling the same name in the same window. Green is buying, red is selling.

SEC EDGAR 13F + Form 4 + US House STOCK Act{ }get_ticker_confluence · API & MCP

Signals by source

Insiders and Congress: last 180 days. Funds: latest 13F, top 100 holders incl. passive

SourceBuyingSellingNet
13F funds
Top 100 holders by value, passive included; the hero counts active managers only
146
Insiders
Form 4 open-market
01-$63K
US House
STOCK Act trades
00$0
Sector rotation
SPRO is in Health Care, which smart money is rotating OUT OF
$5.0B

Capital Rotation reports where institutional capital disclosed rotating, as of the latest public SEC 13F filings. It is data, not investment advice, a recommendation, or a prediction. Filings lag about 45 days and cover long US equity positions only. Past disclosed flows do not indicate future prices. Do your own research; consult a licensed advisor.

Institutional ownership over time

11 tracked filers in Q2 2026 filingsstill filing
02244Q3 2024Q1 2025Q3 2025Q1 2026Q2 2026
tracked filers holding their reported valueQ2 2026 filings so far: $3.9M
Each bar counts tracked filers with a position in that quarter's filings, so the newest bar excludes filers still on an earlier quarter. Arkolith's tracked universe has grown over this window; part of any long-run rise is coverage, not new buyers.

Recent filings

15 most recent

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Connected entities for SPRO

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Ask your agent what changed in SPRO

This stock page is the public Follow view. For one current, evidence-backed answer, use capital_change_brief through REST or MCP. It compares tracked 13F changes with qualifying Form 4 activity and cites the SEC evidence.

Copy-paste
curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://arkolith.com/api/v1/stocks/SPRO/capital-change-brief"
Ask your agent
Use Arkolith's capital_change_brief for SPRO.
Tell me what changed, whether insider activity
corroborates it, and cite the SEC evidence.

13F holdings + Form 4 insider transactions + end-of-day price history + the live filing stream, joined for SPRO. Filings are public domain, sourced to SEC EDGAR; price series derived from end-of-day closes.