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Public filings, plainly told
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CTKB Insider Trading and Fund Holdings (Cytek Biosciences, Inc.) · https://wallstpal.com/stock/ctkb/ · saved 2026-10-28

About this page

Insider trades reported on SEC Form 4: when the people who run a company buy or sell its shares with their own money.

How to read it

Form 4
The form a company insider (officer, director or owner of more than 10%) must file with the SEC within two business days of buying or selling the company's shares.
Buy (P) and Sell (S)
Open-market purchases and sales. Gifts, option exercises and automatic tax withholding are left out because they say little about what the insider thinks.
Value
Shares times price, as reported on the filing.
10b5-1
A trade made under a plan set up in advance. Planned sales are common and usually say less than an unplanned purchase.
Late filing
A Form 4 filed more than two business days after the trade.
Vs. S&P 500
How the stock did after the trade minus how the overall market did in the same weeks.

A real example

In January 2016, when bank stocks were falling, JPMorgan Chase CEO Jamie Dimon bought 500,000 JPMorgan shares with his own money, worth about $26 million. His Form 4 made the purchase public within days, and investors read it as a strong sign of confidence.

Explain it like I'm 13

If the coach of a team bets his own allowance that his team will win, that tells you something. A Form 4 is the note a company boss must hand in whenever he buys or sells his own company's shares, so everyone can see it.

Data from public SEC filings and congressional reports. Information, not investment advice. Check every number against the filing linked on the page.

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StockSEC filings

Cytek Biosciences, Inc. (CTKB): Insider Trades and Fund Holdings

What insiders and tracked funds have reported about Cytek Biosciences, Inc. in SEC filings.

0Insider buys, 12 months
$0Bought by insiders, 12 months
$0Sold by insiders, 12 months
1Tracked funds holding

Timeline: news and trades

Company filings (8-K), insider trades, notices of planned sales (Form 144) and fund moves in the past year, newest first.

  1. Sep 2, 2026Planned salePHILIPPE BUSQUE (officer) filed notice to sell about $146,515 around Sep 2, 2026
  2. Jun 30, 2026FundRenaissance Technologies cut 2% in Q2 2026 (13F filed Aug 13, 2026)

Buybacks and executive pay

Cytek Biosciences, Inc. spent $15.1 million buying back its own shares in 2025.

YearCEO pay reportedCEO pay "actually paid"Value of $100 invested
2025$5.12M$3.64Mn/a
2024$6.08M$4.40Mn/a
2023$4.94M$3.72Mn/a

From the company's XBRL data filed with the SEC. "Actually paid" is the SEC's pay-versus-performance measure, which counts changes in the value of stock awards. "Value of $100 invested" is the company's cumulative shareholder return as reported, usually measured from five years earlier. See all buybacks and CEO pay across companies.

Tracked funds that report CTKB

From each fund's latest 13F. Holdings are as of quarter end and are filed up to 45 days later.

FundQuarterSharesValue% of portfolioChange
Renaissance TechnologiesQ2 2026661,300$2.93M0.00%▼ −2.3%
Source: SEC Form 13F-HR filings, retrieved Oct 28, 2026. How we read filings

Reading these numbers

Insiders sell for many reasons: taxes, diversification, a house. Purchases with their own money are rarer and are usually read as more informative. A Form 4 is due within two business days of the trade. How to read a Form 4 →