RLYB

Rallybio Corp Cross-source read$17.22 4.30%
Health CareCUSIP 75120L209· EOD Sep 15, 2026

Among active 13F managers last quarter, 6 opened and 2 added, while 6 reduced; the largest holder to move was Balyasny Asset Management L.P. (new position). Over the last 180 days, 1 insider bought and none sold, a net +$4.2M in open-market trades.

Tracked 13F holders
34
13F value (tracked)
$45.4M
Smart-money readMixed
Net sellingNet buying
Funds · active managers, latest 13F
8 adding · 6 trimming
Insiders · Form 4 open-market, 180d
1 buying · 0 selling · +$4.2M
US House · STOCK Act, 180d
0 buying · 0 selling

The legs disagree, or only one of them leans.

Price & smart-money activity

$17.22 4.30%5Y -80.1%
$1.84$43.05$84.26$125.47$166.682021202220232024202520268482191436
Hover for who · click for detailEnd-of-day closing prices52w $3.99 – $17.22

Who owns RLYB?

34 tracked 13F filers · ranked by shares held

34 tracked 13F filers disclose a position in RLYB as of the latest SEC 13F filings, a combined $45.4M 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
1FMR LLC795K
$12.7M
+0.1%
Added · +1K sh
Q2 2026
2Viking Global Investors LP524K
$8.4M
Held
Q2 2026
3TPG GP A, LLC379K
$6.1M
Held
Q2 2026
4Balyasny Asset Management L.P.377K
$3.4M
New
+377K sh
Q1 2026
5Nantahala Capital Management, LLC188K
$3.0M
−37%
Reduced · −112K sh
Q2 2026
6Vanguard Capital Management LLC172K
$2.8M
+54%
Added · +60K sh
Q2 2026
7Renaissance Technologies LLC157K
$1.4M
−81%
Reduced · −679K sh
Q1 2026
8Almitas Capital LLC121K
$1.9M
−37%
Reduced · −71K sh
Q2 2026
9Rangeley Capital, LLC105K
$1.7M
+248%
Added · +75K sh
Q2 2026
10Citadel Advisors LLC72K
$1.2M
+263%
Added · +52K sh
Q2 2026
11Mariner, LLC51K
$454K
−88%
Reduced · −354K sh
Q1 2026
12Geode Capital Management, LLC32K
$513K
−9.5%
Reduced · −3K sh
Q2 2026
13BlackRock, Inc.30K
$485K
+73%
Added · +13K sh
Q2 2026
14GTS Securities LLC22K
$197K
New
+22K sh
Q1 2026
15ADAR1 Capital Management, LLC21K
$184K
New
+21K sh
Q1 2026
16Vanguard Fiduciary Trust Co17K
$269K
+24%
Added · +3K sh
Q2 2026
17State Street Corp13K
$208K
New
+13K sh
Q2 2026
18Quadrature Capital Ltd13K
$208K
New
+13K sh
Q2 2026
19Dimensional Fund Advisors LP11K
$101K
New
+11K sh
Q1 2026
20XTX Topco Ltd11K
$101K
−88%
Reduced · −86K sh
Q1 2026
21UBS Group AG8K
$71K
+73%
Added · +3K sh
Q1 2026
22JPMorgan Chase & Co2K
$20K
30×
Added · +2K sh
Q1 2026
23Vanguard Global Advisers, LLC1K
$23K
Held
Q2 2026
24Tower Research Capital LLC (TRC)907
$8K
−80%
Reduced · −4K sh
Q1 2026
25Hartford Financial Management Inc.812
$13K
Held
Q2 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 RLYB being bought or sold by institutions?

Last quarter, 6 funds opened a new position in RLYB and 2 added to an existing one, while 6 reduced. Based on 13F filings from active, signal-eligible managers (passive index funds and other mechanical holders are excluded from this count).

Opened
6
funds took a first position
Added
2
added to an existing position
Reduced
6
reduced, still holding
Biggest moves · ranked by size of the change, positions above a floor

Funds that own RLYB also own

CompanyCo-held byTheir position there
Visa Inc-Class A SharesV13 funds$2.9B
JPMorgan Chase & CoJPM13 funds$2.1B
Eli Lilly & CoLLY13 funds$1.4B
Boeing CoBA13 funds$1.3B
Unitedhealth Group IncUNH13 funds$963.2M
Qualcomm IncQCOM13 funds$750.4M
Union Pacific CorpUNP13 funds$739.2M
Cme Group IncCME13 funds$662.0M
Vertex Pharmaceuticals IncVRTX13 funds$504.5M
Newmont CorpNEM13 funds$430.8M
Bristol-Myers Squibb CoBMY13 funds$168.4M
Amazon.com IncAMZN12 funds$4.8B

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

Insider activity (Form 4)

Full insider page →
Buys · 180d
$4.2M
1 insider
Net · 180d
$4.2M
14 open-market transactions
DateInsiderRoleActionSharesValue
May 19, 2026ADAR1 Capital Management, LLC10% OwnerBuy (P)
2 lots, same day
10K$143K
May 18, 2026ADAR1 Capital Management, LLC10% OwnerBuy (P)6K$84K
May 15, 2026ADAR1 Capital Management, LLC10% OwnerBuy (P)
2 lots, same day
300$4K
May 13, 2026ADAR1 Capital Management, LLC10% OwnerBuy (P)
2 lots, same day
79K$1.1M
May 12, 2026ADAR1 Capital Management, LLC10% OwnerBuy (P)800$11K
May 11, 2026ADAR1 Capital Management, LLC10% OwnerBuy (P)
3 lots, same day
50K$700K
May 5, 2026ADAR1 Capital Management, LLC10% OwnerBuy (P)35K$491K
May 4, 2026ADAR1 Capital Management, LLC10% OwnerBuy (P)
2 lots, same day
121K$1.7M
Feb 23, 2026Lieber Jonathan IChief Financial OfficerSell (S)789$4K
Mar 14, 2023Lieber Jonathan ISee RemarksBuy (P)5K$26K
Mar 7, 2023Schwab Andrew J.10% OwnerSell (S)100K$820K
Mar 7, 2023Parmar KushDirectorSell (S)100K$820K

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?

Confluence: insiders and funds buying

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
812
Insiders
Form 4 open-market
10+$4.2M
US House
STOCK Act trades
00$0
Sector rotation
RLYB is in Health Care, which smart money is rotating OUT OF
$7.6B

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.

Recent filings

15 most recent

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Connected entities for RLYB

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Ask your agent what changed in RLYB

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