MCRB

Seres Therapeutics Inc Cross-source read$5.01 1.76%
Health CareCUSIP 81750R201· EOD Sep 11, 2026

Among active 13F managers last quarter, 3 opened and 4 added, while 2 reduced; the largest holder to move was Marshall Wace, LLP (+16%). Over the last 180 days, 4 insiders sold and none bought, a net -$6K in open-market trades.

Tracked 13F holders
32
8 in Q2 2026 filings
13F value (tracked)
$18.4M
Smart-money readMixed
Net sellingNet buying
Funds · active managers, latest 13F
7 adding · 2 trimming
Insiders · Form 4 open-market, 180d
0 buying · 4 selling · -$6K
US House · STOCK Act, 180d
0 buying · 0 selling

The legs disagree, or only one of them leans.

Price & smart-money activity

$5.01 1.76%5Y -95.4%
$3.99$64.63$125.27$185.90$246.542021202220232024202520262876710524724754724544234
Hover for who · click for detailEnd-of-day closing prices52w $4.34 – $28.63

Who owns MCRB?

32 tracked 13F filers · ranked by shares held

32 tracked 13F filers disclose a position in MCRB as of the latest SEC 13F filings, a combined $18.4M 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
1Flagship Pioneering, LLC1.2M
$9.1M
Held
Q2 2026
2Vanguard Capital Management LLC288K
$2.3M
−2.2%
Reduced · −6K sh
Q2 2026
3Marshall Wace, LLP140K
$1.2M
+16%
Added · +19K sh
Q1 2026
4Vontobel Holding Ltd.123K
$970K
−11%
Reduced · −15K sh
Q2 2026
5BlackRock, Inc.111K
$876K
+8.8%
Added · +9K sh
Q2 2026
6Susquehanna International Group, LLP105K
$934K
−41%
Reduced · −75K sh
Q1 2026
7Geode Capital Management, LLC80K
$631K
+6.9%
Added · +5K sh
Q2 2026
8American Century Companies Inc62K
$553K
+283%
Added · +46K sh
Q1 2026
9Vanguard Fiduciary Trust Co49K
$384K
+23%
Added · +9K sh
Q2 2026
10State Street Corp34K
$267K
Held
Q2 2026
11Charles Schwab Investment Management Inc32K
$281K
+0.8%
Added · +261 sh
Q1 2026
12Morgan Stanley22K
$192K
−14%
Reduced · −3K sh
Q1 2026
13Two Sigma Investments, LP19K
$167K
−27%
Reduced · −7K sh
Q1 2026
14Northern Trust Corp15K
$131K
Held
Q1 2026
15Citadel Advisors LLC11K
$83K
Added
Added · +11K sh
Q2 2026
16UBS Group AG7K
$62K
+66%
Added · +3K sh
Q1 2026
17Barclays PLC7K
$58K
−12%
Reduced · −925 sh
Q1 2026
18SBI Securities Co., Ltd.4K
$33K
+20%
Added · +700 sh
Q2 2026
19Group One Trading LLC4K
$29K
+351%
Added · +3K sh
Q2 2026
20Simplex Trading, LLC3K
$27K
+149%
Added · +2K sh
Q1 2026
21Vanguard Global Advisers, LLC2K
$16K
Held
Q2 2026
22FMR LLC2K
$12K
−13%
Reduced · −224 sh
Q2 2026
23Rachor Investment Advisory Services, LLC1K
$12K
Held
Q2 2026
24Tower Research Capital LLC (TRC)794
$7K
New
+794 sh
Q1 2026
25BNP Paribas Financial Markets211
$2K
−73%
Reduced · −562 sh
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 MCRB being bought or sold by institutions?

Last quarter, 3 funds opened a new position in MCRB and 4 added to an existing one, while 2 reduced. Based on 13F filings from active, signal-eligible managers (passive index funds and other mechanical holders are excluded from this count).

Opened
3
funds took a first position
Added
4
added to an existing position
Reduced
2
reduced, still holding
Biggest moves · ranked by size of the change, positions above a floor

Funds that own MCRB also own

CompanyCo-held byTheir position there
Nvidia CorpNVDA10 funds$19.3B
Apple IncAAPL10 funds$13.1B
Amazon.com IncAMZN10 funds$11.7B
Microsoft CorpMSFT10 funds$10.1B
Alphabet Inc-CL AGOOGL10 funds$9.2B
Broadcom IncAVGO10 funds$6.5B
Tesla IncTSLA10 funds$5.2B
Mastercard Inc - AMA10 funds$4.7B
Meta Platforms Inc-Class AMETA10 funds$4.6B
Taiwan Semiconductor-SP ADRTSM10 funds$3.8B
Eli Lilly & CoLLY10 funds$3.7B
Costco Wholesale CorpCOST10 funds$3.5B

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

Insider activity (Form 4)

Full insider page →
Sells · 180d
$6K
4 insiders
Net · 180d
-$6K
8 open-market transactions
DateInsiderRoleActionSharesValue
Aug 17, 2026DesRosier ThomasSee RemarksSell (S)82$373
Aug 17, 2026Henn Matthew RSee RemarksSell (S)81$369
Aug 17, 2026Shaff Eric D.DirectorSell (S)263$1K
Aug 17, 2026Brady KellySee RemarksSell (S)64$291
May 18, 2026DesRosier ThomasSee RemarksSell (S)79$595
May 18, 2026Brady KellySee RemarksSell (S)59$444
May 18, 2026Henn Matthew RSee RemarksSell (S)77$580
May 18, 2026Shaff Eric D.DirectorSell (S)259$2K
Feb 15, 2026Henn Matthew RSee RemarksSell (S)89$754
Feb 15, 2026DesRosier ThomasSee RemarksSell (S)78$661
Feb 15, 2026Shaff Eric D.DirectorSell (S)259$2K
Feb 15, 2026Young Teresa L.See RemarksSell (S)75$635

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
129
Insiders
Form 4 open-market
04-$6K
US House
STOCK Act trades
00$0
Sector rotation
MCRB 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

8 tracked filers in Q2 2026 filingsstill filing
01733Q1 2025Q2 2025Q3 2025Q4 2025Q1 2026Q2 2026
tracked filers holding their reported valueQ2 2026 filings so far: $1.9M
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 MCRB

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Ask your agent what changed in MCRB

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/MCRB/capital-change-brief"
Ask your agent
Use Arkolith's capital_change_brief for MCRB.
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 MCRB. Filings are public domain, sourced to SEC EDGAR; price series derived from end-of-day closes.