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Insider profile

Casdin Partners Master Fund, L.P. Insider Trading

This page tracks every SEC Form 4 filing since April 2023 by Casdin Partners Master Fund, L.P.: 111 transactions in total, including 80 open-market purchases and 9 sales. Each record is parsed directly from the original filing, with amendments reconciled so a corrected filing never double-counts.

Role
Director
CIK
0001534265
Companies traded
3
Total filings
111
First filing
2021-09-01
Last filing
2026-06-05

Files as Casdin Partners Master Fund, L.P. · SEC EDGAR ↗

Activity summary

The most recent open-market decision was a purchase of 50,000 shares ($2.6M) on June 5, 2026.

Three year balance

Buy and sell value by quarter, Q3 23 to Q2 26. Casdin Partners Master Fund, L.P. has been a net buyer across the period shown.

PurchasesSales
Q3 23Q4 23$132.9MQ1 24Q2 24Q3 24Q4 24Q1 25Q2 25Q3 25Q4 25Q1 26Q2 26

Bars below the rule are sales, above are purchases. Largest quarter on the chart is $132.9M.

Insider insight

Casdin Partners Master Fund, L.P. trades most actively in LAB, accounting for 27 of the 111 filings on record. The largest single open-market purchase on record is $9.8M in LAB, filed Nov 2025.

Track record

$102.2M
Total purchased
$157.6M
Total sold
40
32 buys · 8 sales
Net seller
Overall direction

Most active in

LAB27 buysBLFS7 salesWGS5 buys · 1 sale

Avg buy vs sell price

WGS$47.65→$120.90+153.7%

Average prices across open-market transactions in this dataset.

Largest trade: $9.8M in LAB (Nov 2025) in last 50Filing history: Sep 2021 — Jun 2026Under a 10b5-1 plan: 0%Full history: 111 filings

Transaction History

Sourced from SEC EDGAR Form 4 filings. Updated hourly.

DateInsiderCompanyTypeSharesPriceValueReturn
Jun 5, 2026Casdin Partners Master Fund, L.P.WGS
Purchase
50,000$52.86$2.64M+65.8% 3m
Jun 4, 2026Casdin Partners Master Fund, L.P.WGS
Purchase
150,000$56.44$8.47M+65.8% 3m
May 21, 2026Casdin Partners Master Fund, L.P.BLFS
Sale
650,000$23.70$15.40M+50.0% 3m
May 20, 2026Casdin Partners Master Fund, L.P.BLFS
Sale
250,000$23.70$5.92M+50.0% 3m
May 20, 2026Casdin Partners Master Fund, L.P.WGS
Purchase
140,000$43.81$6.13M+84.6% 3m

45 more transactions hidden

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Companies traded

By number of filings.

LAB27 filings
BLFS7 filings
WGS6 filings

Based on the last 50 filings on file — this insider has a longer history.

Filing cadence

Filings per quarter, this window.

6.3filings / quarter, Q3 24–Q2 26

Busiest: Q4 25 (16 filings)

Quietest: Q4 24 (0 filings)

Based on the last 50 filings on file — this insider has a longer history.

Reading an insider's Form 4 history

Corporate insiders — directors, officers, and holders of more than 10% of a company's stock — must report their trades to the SEC on Form 4 within two business days. Looking at one insider's filings over time shows whether they tend to buy on the open market (a discretionary use of their own money, generally the strongest signal), sell, or simply receive and exercise equity awards as compensation.

The track record above measures how this insider's past open-market purchases performed in the months after each filing. Trades made under a pre-scheduled Rule 10b5-1 plan are flagged because they carry no timing signal. To pull any insider's full history programmatically, see the insider trading API or our guide to reading Form 4 filings.

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Form4API, StockholmNot affiliated with the SEC or EDGAR. Data sourced from public EDGAR filings. Not investment advice.

Scorecard

44%
Buys positive after 3m
+11.8%
Avg return at 3m
-2.4%
Median return at 3m
73
Scored buys
Best buy: WGS+238.9% 3m (Mar 2024)Worst buy: BLFS-49.4% 3m (May 2023)

Absolute post-filing return, not market-adjusted · min. 5 matured open-market buys

See top insiders by track record →

Related insiders

Other insiders filing on LAB.

Eli Casdin33 filingsCasdin Capital, LLC10% ownerCasdin Partners GP, LLC10% owner