Stock Trading Canary

United States · SEC Form 4 · Snapshot date: 2026-10-18 · Built: 2026-10-18 · 中文

← United States · Coverage record

US · SEC FORM 4

Cytek Biosciences, Inc.

CTKB · Nasdaq · CIK 0001831915 · Healthcare · Medical Devices

INSIDER SIGNAL

No active buy signal

0 qualifying P purchase groups
in the current 180-day scoring window

70 Form 4 transaction lines observed in the same window
0 sales · 70 option, withholding, award, gift or other lines

Last qualifying purchase2025-06-02 · McCombe William D. · $97.3K

WHY NO ACTIVE SIGNAL?

Purchase activityNone
Recent buyingNone
Recent salesNone
Buy signal statusInactive
Score anatomy

No score is calculated because there is no qualifying purchase in the active window. Unavailable inputs are not treated as zero or as a bearish signal.

ClusterNot calculated
Purchase sizeNot calculated
RoleNot calculated
RecencyNot calculated
ConvictionNot calculated

Why is there no score?

  • No qualifying open-market purchase supplies cluster, size, role, recency or conviction inputs.
  • Sales and other Form 4 activity remain visible as context and do not create a negative score.

Sales and other Form 4 activity are shown separately and do not create a negative buy signal. Absence of buying is not scored as bearish.

Insider activity timeline

Owner lanes show the latest 180 days. Symbol shape identifies the transaction type; sales remain context only.

AprMayJunJulAugSepOct
Yan MingCHIEF TECHNOLOGY OFFICER
○○○○○
Jiang WenbinPRESIDENT AND CEO
○○○○
McCombe William D.Chief Financial Officer
○○○○
Holder MichaelDirector
○○○
Chin RichardDirector
○○
Busque PhilippeSVP, GLOBAL SALES AND SERVICES
○○
● Purchase▼ Sale○ Other

Showing the six most active owners; 5 additional owner(s) remain in Form 4 evidence.

Purchase breadth, concentration & cluster buying

These modules activate when qualifying purchases enter the 180-day research window.

SIGNAL HISTORY

No recorded active-signal snapshot

Scores are archived only when the company qualifies for a published US buy-signal snapshot. Last qualifying purchase: 2025-06-02 · McCombe William D..

Recent Form 4 activity

0Purchases
0Sales
143Other Form 4 lines
36SEC filings · 365 days
BUYING0 qualifying P line(s) · 180 days
SELLING0 sale line(s) · context only
OTHER70 exercise / withholding / award / gift / other lines
10b5-1 / PLANNEDNot assessed

P is an open-market or private purchase. S is a sale. M, F, A and G usually describe exercises, tax withholding, awards and gifts. These categories remain visually separate.

Market context

Market context has not been captured for this ticker yet. The daily market-context job processes the US universe in rotating batches.

Short interest

Short interest is external context reported to FINRA by broker-dealers. It does not affect the Insider Signal.

Shares short
5,215,595
Previous report
5,242,079
Avg daily volume
1,666,297
Days to cover
3.1

FINRA settlement date: 2026-09-30 · Captured 2026-10-12 · FINRA equity short interest ↗. A share count, published about a week after each of two settlement dates a month; not a percentage of shares outstanding.

Historical equity purchases

Qualifying code P transactions in the local Form 4 history, including purchases outside the current signal window.

Transaction dateReporting ownerTypeSecuritySharesAvg. priceApprox. valueSource
2025-06-02McCombe William D.Purchase (P)Common Stock35,000USD 2.78USD 97,300SEC filing ↗
2022-03-15Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock241,727USD 12.27USD 2,965,990SEC filing ↗
2022-03-14Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock342,143USD 12.35USD 4,225,466SEC filing ↗
2022-03-11Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock337,492USD 12.77USD 4,309,773SEC filing ↗
2022-03-10Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock256,992USD 12.95USD 3,328,046SEC filing ↗
2022-03-09Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock40,154USD 12.99USD 521,600SEC filing ↗
2022-03-08Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock245,701USD 12.86USD 3,159,715SEC filing ↗
2022-03-07Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock337,901USD 12.61USD 4,260,932SEC filing ↗
2022-03-04Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock63,662USD 12.99USD 826,969SEC filing ↗
2022-03-02Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock138,255USD 12.89USD 1,782,107SEC filing ↗
2022-03-01Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock294,864USD 12.98USD 3,827,335SEC filing ↗
2022-02-28Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock8,746USD 12.97USD 113,436SEC filing ↗
2022-02-25Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock18,991USD 12.99USD 246,693SEC filing ↗
2022-02-24Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock186,467USD 13.03USD 2,429,665SEC filing ↗
2022-02-23Kolchinsky Peter; RA CAPITAL MANAGEMENT, L.P.; RA Capital Healthcare Fund LP; RA Capital Nexus Fund II, L.P.; Shah Rajeev M.Purchase (P)Common Stock214,922USD 13.41USD 2,882,104SEC filing ↗

Form 4 evidence

143 transaction lines in the latest 365-day window; 604 in local history.

DateOwnerTypeSecuritySharesAvg. priceApprox. valueSource
2026-08-18Yan MingOption exercise / conversion (M)Common Stock33,270USD —USD —SEC filing ↗
2026-08-18Yan MingTax withholding (F)Common Stock8,088USD 4.67USD 37,771SEC filing ↗
2026-08-18McCombe William D.Option exercise / conversion (M)Common Stock35,420USD —USD —SEC filing ↗
Show recent Form 4 evidence (30 grouped rows)
DateOwnerTypeSecuritySharesAvg. priceApprox. valueSource
2026-08-18Yan MingOption exercise / conversion (M)Common Stock33,270USD —USD —SEC filing ↗
2026-08-18Yan MingTax withholding (F)Common Stock8,088USD 4.67USD 37,771SEC filing ↗
2026-08-18McCombe William D.Option exercise / conversion (M)Common Stock35,420USD —USD —SEC filing ↗
2026-08-18McCombe William D.Tax withholding (F)Common Stock11,904USD 4.67USD 55,592SEC filing ↗
2026-08-18MUIR GLENN POption exercise / conversion (M)Common Stock3,086USD —USD —SEC filing ↗
2026-08-18Jiang WenbinOption exercise / conversion (M)Common Stock120,095USD —USD —SEC filing ↗
2026-08-18Jiang WenbinTax withholding (F)Common Stock36,269USD 4.67USD 169,376SEC filing ↗
2026-08-18Holder MichaelOption exercise / conversion (M)Common Stock2,181USD —USD —SEC filing ↗
2026-08-18Chin RichardOption exercise / conversion (M)Common Stock6,107USD —USD —SEC filing ↗
2026-06-12Yan MingGift (G)Common Stock135,892USD 0.00USD 0SEC filing ↗
2026-06-10NEFF DEBORAH JOption exercise / conversion (M)Common Stock43,973USD —USD —SEC filing ↗
2026-06-10Imper VeraOption exercise / conversion (M)Common Stock43,973USD —USD —SEC filing ↗
2026-06-10Holder MichaelOption exercise / conversion (M)Common Stock43,973USD —USD —SEC filing ↗
2026-06-10Ball JackOption exercise / conversion (M)Common Stock43,973USD —USD —SEC filing ↗
2026-05-18Yan MingOption exercise / conversion (M)Common Stock22,179USD —USD —SEC filing ↗
2026-05-18Yan MingTax withholding (F)Common Stock5,532USD 3.55USD 19,639SEC filing ↗
2026-05-18McCombe William D.Option exercise / conversion (M)Common Stock25,719USD —USD —SEC filing ↗
2026-05-18McCombe William D.Tax withholding (F)Common Stock9,229USD 3.55USD 32,763SEC filing ↗
2026-05-18Jiang WenbinOption exercise / conversion (M)Common Stock80,062USD —USD —SEC filing ↗
2026-05-18Jiang WenbinTax withholding (F)Common Stock25,542USD 3.55USD 90,674SEC filing ↗
2026-05-18Holder MichaelOption exercise / conversion (M)Common Stock1,454USD —USD —SEC filing ↗
2026-05-18Chin RichardOption exercise / conversion (M)Common Stock6,107USD —USD —SEC filing ↗
2026-05-18Busque PhilippeOption exercise / conversion (M)Common Stock10,464USD —USD —SEC filing ↗
2026-05-18Busque PhilippeTax withholding (F)Common Stock2,685USD 3.55USD 9,532SEC filing ↗
2026-05-18Barnett ValerieOption exercise / conversion (M)Common Stock24,295USD —USD —SEC filing ↗
2026-05-18Barnett ValerieTax withholding (F)Common Stock8,719USD 3.55USD 30,952SEC filing ↗
2026-03-13Yan MingGift (G)Common Stock1,176,000USD 0.00USD 0SEC filing ↗
2026-03-10Yan MingOption exercise / conversion (M)Common Stock25,400USD —USD —SEC filing ↗
2026-03-10Yan MingTax withholding (F)Common Stock7,731USD 4.23USD 32,702SEC filing ↗
2026-03-10McCombe William D.Option exercise / conversion (M)Common Stock23,721USD —USD —SEC filing ↗

Multiple price lines in one filing are grouped and share-weighted. Price and value are blank when a grouped filing line lacks price evidence.

Snapshot & identity

Snapshot date2026-10-18
Ranking versionUS-v1.2
Data qualityPASS ELIGIBLE · —
TickerCTKB
CIK0001831915
SectorHealthcare
IndustryMedical Devices Yahoo Finance
SEC SIC3826 Laboratory Analytical Instruments
ExchangeNasdaq

Data coverage

Local Form 4 history604 transaction lines from 2021-07-22 to 2026-08-18
27 P purchase lines · 75 S sale lines · 502 other lines
SEC company submissionsOpen SEC filings ↗

Local ledger as of 2026-10-18. Mapping status is an audit field and does not erase SEC filing evidence.