PLYX Polaryx Therapeutics (PLYX) Insider Trading, Ownership & Congress Trades

Pharma & Biotech · Pharmaceutical preparations · CIK 0002075320

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C-suite buying · 1

House members buying, 1 year

STOCK Act, US House only, disclosed up to 45 days after the trade

Funds added, last quarter

13F, latest reported quarter

What the filings say about PLYX

Insiders, 180 days

+$360.0K net bought

1 buyer

Polaryx Therapeutics insider trades (Form 4)

Form 4 buys and sells (codes P and S). Grants, option exercises and conversions excluded.

Over the last 180 days, Polaryx Therapeutics, Inc. insiders bought a net $360.0K of stock across 2 Form 4 purchases and sales, with 1 insider buying. Source: SEC Form 4 filings, as of 2026-10-28.

Insider

Filed

Value

Since filing

Mstone Partners Healthcare Ltd

Chief Executive Officer

BUY

2026-05-28 SECtraded 2026-05-27

88,453

$360.0K

-44.3%

Context

First Form 4 purchase or sale (code P or S) here by this insider on our record.
The trade is 0.4% of the 24,233,249 shares held after it.
No other insider bought within 30 days.
7 funds added in the 13F quarter to Jun 30, 2026.

Insider activity: Chief Executive Officer Mstone Partners Healthcare Ltd bought about $360.0K of PLYX on May 27, 2026, the largest insider purchase at the company on our record; 7 funds added in the latest 13F quarter.

Landis G. Michael

Chief Financial Officer

BUY

2026-02-20 SECtraded 2026-02-18

2,867

$8.0K

-26.3%

Context

First Form 4 purchase or sale (code P or S) here by this insider on our record.
The trade is 1.3% of the 228,225 shares held after it.
No other insider bought within 30 days.
7 funds added in the 13F quarter to Jun 30, 2026.

Insider activity: Chief Financial Officer Landis G. Michael bought about $8.0K of PLYX on Feb 18, 2026, the largest insider purchase at the company on our record; 7 funds added in the latest 13F quarter.

2 transactions on record · a thin record, read with care

Since filing: total return from the first close after the filing to the latest close, dividend-adjusted. Not a forecast.

Context lines are counts over the filings above and returns from our own price history, never a price level. Not investment advice.

See all insider buying · insider selling

Seven facts, ranked against the sector · Rank is not a forecast

Insiders

net +$360.0K over 180 days

+$360.0K of it by a 10%+ holder

more than 83% of Pharma & Biotech

Congress

no House purchase disclosed in the last 12 months

Funds

7 funds bought in last quarter

below 91% of Pharma & Biotech

Revenue

no revenue reported in any filing

Margin

no margin: no revenue reported

Buybacks

no share repurchases reported

Short interest

2.0% of the float short (float per yahoo 2026-10-26) · 4.5 days to cover · settled 2026-09-30

below 84% of Pharma & Biotech

What changed in the last 30 days

Nothing new filed in the last 30 days

Watch PLYX

A free account keeps a watchlist and can send one email a day when insiders, funds or Congress file on the names in it. No password and no card.

The year, with the filings on it

Total return over 12 months. Each marker is a filing; hover or tap one for the detail.

-94.8%12M

Insider buy13D/G stake

Indexed to 100, dividend-adjusted, not a price chart. When a name files heavily, the largest trades are drawn first.

Who owns PLYX: institutional holders (13F)

13F holdings, latest reported quarter

VANGUARD CAPITAL MANAGEMENT LLC

1,657,872 sh

$4.4M

GEODE CAPITAL MANAGEMENT, LLC

170,998 sh

$455.1K

VANGUARD FIDUCIARY TRUST CO

105,072 sh

$279.5K

STATE STREET CORP

58,104 sh

$154.6K

BlackRock, Inc.

41,012 sh

$109.1K

Congress trades in PLYX

No Congress trades reported

No House member has disclosed a trade in this stock. See what Congress is buying.

Activist and 5% holders (13D/13G)

13D: intends to influence · 13G: passive

Mstone Partners Healthcare Limited

Activist 13D · 2026-02-05

47.4%

MBstone Biotech Flagship Limited

Activist 13D · 2026-02-05

0.4%

Mstone Pediaorphan Singapore I Pte. Limited

Activist 13D · 2026-02-05

0.2%

Alex Keun Mo Yang

Activist 13D · 2026-02-05

48.0%

PLYX planned insider sales (Form 144)

No planned-sale notices

No insider has filed to sell. Watch this after a run-up.

PLYX mutual fund holders (N-PORT)

Funds ranked by the share of their own portfolio in this stock (N-PORT).

Fidelity Extended Market Index Fund

$219.3K position · as of 2026-05-31

0.0%

VANGUARD EXTENDED MARKET INDEX FUND

$377.8K position · as of 2026-06-30

0.0%

Fidelity Nasdaq Composite Index Fund

$93.7K position · as of 2026-05-31

0.0%

Total Stock Market Index Trust

$2.3K position · as of 2026-06-30

0.0%

VANGUARD TOTAL STOCK MARKET INDEX FUND

$3.9M position · as of 2026-06-30

0.0%

VANGUARD INSTITUTIONAL TOTAL STOCK MARKET INDEX FUND

$58.1K position · as of 2026-06-30

0.0%

SEC N-PORT, monthly, about 60 days late · funds ≥ $10M · % is the share of the fund's own portfolio

Clinical pipeline

2 registered trials, 1 still running (ClinicalTrials.gov). A status change is dated here weeks before the press release.

Phase 2

1 active

Phase 3

0 active

Matched by sponsor name. Trials run under a subsidiary's own name are not included.

Live price

Daily candles from TradingView, under their licence. No filings marked.

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Why this name is on the desk

Insiders are net buyers of their own stock.

The record shows a net $360.0K bought by insiders over 180 days, 7 funds added last quarter. Each figure is a federal filing, dated the day it went public.

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Same sector, ranked by filing activity

Sector by SEC SIC code

UTHR CPIX MRNA REGN LLY ALNY MDGL CITR DNA VRTX NUVL TWST

PLYX financials

Fundamentals

Annual figures from XBRL filings. Pick a past date to see them as known then.

	2025-12	2024-12
Operating income	-$7.8M	-$4.4M
Net income	-$9.0M	-$30.4M
EPS (diluted)	-0.20	-0.89
Operating cash flow	-$3.9M	-$2.6M
Cash	$5.1M	$4.6M

SEC XBRL, fiscal years, as known on 2026-10-28

PLYX Stock Sonar score 3/7 axes

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PLYX ranks highest on risk and compliance (74th percentile) and insider conviction (70th), and lowest on institutional and government (9th), among Pharma & Biotech peers.

Insider conviction

Inputs

Net Form 4 buying (codes P and S), 180d$360K · 83 pct, sector of 428
Insider buyers, 180d1 · 56 pct, sector of 437

Institutional and government

Inputs

Funds adding, latest quarter7 · 9 pct, sector of 698
Congress net buyers, 365dno Congress trades in 365 days
Federal contracts, 180dno federal contracts in 180 days
Lobbying spend, 4 quartersno lobbying filings in the last four quarters

Risk and compliance

Inputs

Short interest, % of float+2.0% · 74 pct, sector of 813
Recalls per $1B revenue, 3yrevenue under $50M or not filed, so a count cannot be scaled to size
EPA cases per $1B revenue, 5yrevenue under $50M or not filed, so a count cannot be scaled to size
New text in Risk Factors, latest 10-Kneeds two 10-Ks with a Risk Factors section (not 20-F filers or stubs)

4 not measured: Profitability, Financial health, Growth, US patents

Profitability needs 2 of 4 inputs, 0 present: fewer than four consecutive quarters of net income; fewer than four consecutive quarters of operating income
Financial health needs 1 of 2 inputs, 0 present: no debt line filed
Growth needs 1 of 2 inputs, 0 present: no backlog line filed, or no year-earlier backlog; no revenue for this year and the year before
US patents needs 1 of 2 inputs, 0 present: patent data not loaded yet

3 of 7 axes scored. Each is a percentile against sector peers (all companies when the sector is thin); higher is better. An unscored axis is unmeasured, not low. How it is scored

PLYX filings, in plain words

Are Polaryx Therapeutics insiders buying or selling PLYX?

In the 180 days to 2026-10-28, Polaryx Therapeutics insiders were net buyers, a net $360.0K across purchases and sales reported on Form 4, by 1 buyer.

Read the full summary

In the 180 days to 2026-10-28, Polaryx Therapeutics insiders were net buyers of PLYX, a net $360.0K across purchases and sales reported on Form 4 by 1 buyer. Most of that figure, $360.0K, came from a holder of 10% or more rather than an officer or director. The latest 5% ownership filing is a 13D by Mstone Partners Healthcare Limited, filed 2026-02-05, for 47.4% of the class. Each figure is counted from SEC and House filings as of 2026-10-28, dated the day the filing was made public.

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