Rallybio Corp (RLYB) IPO — S-1 Filing, Stock & Insider Activity

Rallybio Corp IPO — Status & S-1 Filing

Ticker: RLYB
Status: Registration withdrawn
Expected price range: not yet disclosed (set in a later S-1/A or pricing amendment)
SEC CIK: 0001739410 · View the S-1 on SEC EDGAR →

Track every registration update on the InsiderAlpha IPO tracker.

Updated Jul 16, 2026 · Last SEC filing 2026-07-10

Rallybio Corp (RLYB) has filed 5 SEC Form 4 insider transactions in the last 90 days, with the most recent on 2026-07-10. 3 Form 8-K material event filings were reported by RLYB in the last 90 days. InsiderAlpha tracks every RLYB SEC filing — Form 4, Form 144, and 8-K — in real time, including Rule 10b5-1 plan detection.

About Rallybio Corp (RLYB)

SEC CIK	0001739410

90-Day SEC Filing Activity

Form 4 filings (90d)	5
Form 8-K filings (90d)	3
Latest Form 4 filing	2026-07-10

Recent RLYB Insider Transactions (Form 4)

Date	Insider	Role	Transaction	Shares	Price	Value	Filing
2026-07-06	Boudreau Helen M	Insider	M — Option exercise	3.6K	$2.38	$8K	SEC
2026-05-19	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	200	$13.80	$3K	SEC
2026-05-19	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	10.0K	$13.98	$140K	SEC
2026-05-18	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	6.0K	$13.98	$84K	SEC
2026-05-15	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	100	$13.80	$1K	SEC
2026-05-15	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	200	$13.95	$3K	SEC
2026-05-13	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	75.2K	$14.00	$1.05M	SEC
2026-05-13	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	4.1K	$13.80	$56K	SEC
2026-05-12	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	800	$13.83	$11K	SEC
2026-05-11	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	19.9K	$14.00	$279K	SEC
2026-05-11	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	25.0K	$14.00	$350K	SEC
2026-05-11	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	5.1K	$14.00	$71K	SEC
2026-05-05	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	35.1K	$14.00	$491K	SEC
2026-05-04	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	3.9K	$13.90	$54K	SEC
2026-05-04	ADAR1 Capital Management, LLC	10% Owner	P — Open-market purchase	116.9K	$13.97	$1.63M	SEC

All transactions sourced from SEC EDGAR Form 4 filings for Rallybio Corp (RLYB). Updated in real time as new filings are submitted to the SEC.

Most-Active RLYB Insiders — Last 90 Days

Insider	Form 4 filings	Total transaction value
ADAR1 Capital Management, LLC	14	$4.23M
Boudreau Helen M	2	$8K

Recent RLYB Form 8-K Material Events

2026-06-01 — Item 1.01, 3.02, 5.01, 5.02, 7.01, 9.01 [SEC]
2026-06-01 — Other · neutral [SEC]
Trading halt (T1) for RLYB. RLYB
2026-05-04 — Item 1.02, 9.01 [SEC]
2026-03-31 — Item 5.02 · Leadership · negative [SEC]
Steven Ryder, M.D., Chief Medical Officer of Rallybio since January 2019, departed effective immediately on March 31, 2026. Dr. Ryder will receive severance payments under his employment agreement, with additional change-of-control severance due upon closing of Rallybio's pending
2026-03-02 — Item 1.01, 3.02, 5.01, 5.02, 7.01, 9.01 · Acquisition · mixed [SEC]
Rallybio Corporation entered into a definitive Agreement and Plan of Merger with Candid Therapeutics, a clinical-stage biotech company with a T-cell engager (TCE) therapeutic portfolio for autoimmune diseases. Under the merger agreement, Candid will become a wholly-owned subsidia

Recent Insider Filings

2026-07-10 — Boudreau Helen M (Insider)
2026-05-21 — ADAR1 Capital Management, LLC (10% Owner)
2026-05-16 — ADAR1 Capital Management, LLC (10% Owner)
2026-05-14 — ADAR1 Capital Management, LLC (10% Owner)
2026-05-07 — ADAR1 Capital Management, LLC (10% Owner)

Form 4 Transaction Code Reference

SEC Form 4 transactions are reported with a one-letter code indicating the type of transaction. Common codes you'll see in RLYB insider filings:

P	Open-market purchase by the insider
S	Open-market sale by the insider
A	Grant, award, or other acquisition from the issuer
M	Exercise or conversion of derivative security (e.g. options)
F	Payment of exercise price or tax liability via share withholding
G	Bona-fide gift of securities
D	Disposition to the issuer (e.g. share buyback participation)
J	Other acquisition or disposition
X	Exercise of in-the-money or at-the-money derivative security
C	Conversion of derivative security
V	Transaction voluntarily reported earlier than required

RLYB Insider Trading — FAQ

What is the latest insider trade for RLYB?: Rallybio Corp (RLYB) had 5 insider filings in the last 90 days, with the most recent on 2026-07-10. InsiderAlpha tracks every Form 4, 10-K, 10-Q, and 8-K filing in real time.
How many insiders are buying RLYB stock?: 0 insider purchases of RLYB were filed in the last 90 days.
How many insiders are selling RLYB stock?: 0 insider sales of RLYB were filed in the last 90 days.
Where can I see RLYB SEC filings (Form 4, 10-K, 10-Q, 8-K)?: InsiderAlpha aggregates every RLYB SEC filing — Form 4 insider transactions, 10-K and 10-Q quarterly reports, and 8-K material event disclosures — in one timeline.

Learn More

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