SEC ownership of GCT Semiconductor Holding, Inc.

Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001851961.

Comparable stake leader

SUNP Corp

Disclosed value leader

Anapass, Inc.

Comparable rows

45/50

Latest evidence

30 Jun 2026

Top shareholders Insider holders Latest transactions
Public ticker
GCTS, GCTS-WT on NYSE
Parsed ownership sources
13D/G, 3/4/5, and 13F
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
Largest SEC-reported holder
SUNP Corp
Ranking: Comparable ownership first, then disclosed value
Ownership snapshot CIK-linked ownership evidence from parsed SEC filings. 3 signals
Comparable ownership rows
45 of 50
Meaning: Rows with safely comparable ownership %
Latest 13D/G holder
SUNP Corp
Source: Latest parsed Schedule 13D/G stake
Latest parsed ownership date
30 Jun 2026
Freshness: Most recent filing date in this holder set
Issuer Names, identifiers, and filing context for this profile. 2 identity fields
Issuer CIK
0001851961
Issuer location
San Jose, CA

Ownership snapshot

Top shareholders of GCT Semiconductor Holding, Inc. (13F + 13D/G + 3/4/5)

Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.

Comparable stake leader
SUNP Corp
Disclosed value leader
Anapass, Inc.
Comparable rows
45/50
Latest evidence
30 Jun 2026
13D/G 3/4/5 13F Lead comparable stake: 5.2% 5 rows are not safely comparable across share classes. 13D/G row: SUNP Corp Showing 1-8 of 50 holder rows.

Quick read

SUNP Corp leads the comparable SEC ownership view at 5.2%.

45 of 50 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.

Open SEC evidence Opens SUNP Corp's linked filing trail.
Comparable ownership Top 5
SUNP Corp 5.2%
TD SECURITIES (USA) LLC 4.6%
Concord Sponsor Group III LLC 1.3%
Kyeongho Lee 1.5%
Hyunsoo Shin 1.1%

Ownership % is shown only when SEC disclosures are safely comparable across share classes.

Detailed SEC evidence table Showing 1-8 of 50 holder rows
Holder Evidence Ownership % Position 12M Net Δ As of
SUNP Corp
13D/G
13D/G
5.2%
$4,162,544
2,910,870 shares
 -$1,587,905 30 Jun 2025
TD SECURITIES (USA) LLC
13D/G
13D/G
4.6%
$4,597,001
3,456,392 shares
 -$314,831 31 Mar 2026
Concord Sponsor Group III LLC
13D/G 3/4/5
10%+ Owner
13D/G 3/4/5
1.3%
$891,946
632,586 shares
 $0 26 Mar 2025
Kyeongho Lee
3/4/5
Director, Chairman & Class III Director
3/4/5
1.5%
$1,249,579
1,096,122 shares
 — 30 Jun 2026
Hyunsoo Shin
3/4/5
Director, Class II Director
3/4/5
1.1%
$928,037
814,068 shares
 +$300,844 30 Jun 2026
John Schlaefer
3/4/5
President, CEO & Class III Dir, Director
3/4/5
0.27%
$273,682
202,728 shares
 — 26 Sep 2025
Alex Sum
3/4/5
Sr. VP of Sales and Marketing
3/4/5
0.24%
$248,053
183,743 shares
 — 19 Sep 2025
Jeffrey Tuder
3/4/5
Director, Class III Director
3/4/5
0.2%
$453,570
151,190 shares
 — 30 Jun 2026
How to read this table

Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.

Forms 3/4/5 flow

Insider trading overview

Net insider flow leans to buying over the last 12 months. Net value: +$300,844.

Buys
$300,844
Insiders: 1
Sells
$0
Insiders: 0
Net
+$300,844
Shares: +228,975
Window
Last 12 months
4 rolling buckets
Buy value Sell value
Shares: 228,975 Shares: 0
Window (months) Buy shares Sell shares Buy value Sell value Net value
0-3 0 0 $0 $0 $0
3-6 0 0 $0 $0 $0
6-9 45,358 0 $58,058 $0 +$58,058
9-12 183,617 0 $242,786 $0 +$242,786

Reporting owners

Insider holders from Forms 3/4/5

Showing 1-18 of 18 reporting-owner rows connected to GCT Semiconductor Holding, Inc.. Open a relationship link for the CIK-to-CIK filing trail.

Rows
18
Largest Forms 3/4/5 holder
Anapass, Inc.
Net 12M change
+$300,844
Latest report
30 Jun 2026
Name Relationship Holdings Value Past Year Net Change Change % Valuation Report Date
Anapass, Inc. 10%+ Owner $24,212,747 Filing P/S 26 Sep 2024
Kyeongho Lee Director, Chairman & Class III Director $1,249,579 Mixed 30 Jun 2026
Hyunsoo Shin Director, Class II Director $928,037 +$300,844 +48% Mixed 30 Jun 2026
Jeffrey Tuder Director, Class III Director $453,570 Mixed 30 Jun 2026
Jeong-Min Kim Chief Technology Officer $408,646 Mixed 19 Sep 2025
John Schlaefer President, CEO & Class III Dir, Director $273,682 Mixed 26 Sep 2025
Alex Sum Sr. VP of Sales and Marketing $248,053 Mixed 19 Sep 2025
Edmond Cheng Chief Financial Officer $203,850 Mixed 19 Sep 2025
Robert Barker Director, Class II Director $172,949 Mixed 30 Jun 2026
Nelson Chan Director, Class I Director $153,787 Mixed 30 Jun 2026
Kukjin Chun Director, Class I Director $112,445 Mixed 30 Jun 2026
Concord Sponsor Group III LLC 10%+ Owner $69,584 Mixed 26 Mar 2025
Robert E. Diamond Jr. Director Mixed 03 Nov 2021
Michele Cito Chief Financial Officer Mixed 03 Nov 2021
Thomas C. King Director Mixed 16 Nov 2023
David Yoon Vice President of Finance Mixed 26 Mar 2024
Lawrence E. Leibowitz Director Mixed 16 Nov 2023
Peter Ort Director Mixed 16 Nov 2023

Recent insider transactions for GCT Semiconductor Holding, Inc.

Showing up to 300 recent insider transactions from the last 12 months.

Insider Symbol Class Transaction % SEC-reported value SEC-reported price Shares Shares owned Date Ownership
Jeffrey Tuder GCTS Common Stock Award 6.52% 9,259 151,190 30 Jun 2026 Direct
Robert Barker GCTS Common Stock Award 6.5% 9,259 151,710 30 Jun 2026 Direct
Kukjin Chun GCTS Common Stock Award 10.4% 9,259 98,636 30 Jun 2026 Direct
Nelson Chan GCTS Common Stock Award 7.37% 9,259 134,901 30 Jun 2026 Direct
Kyeongho Lee GCTS Common Stock Award 0.85% 9,259 1,096,122 30 Jun 2026 Direct
Hyunsoo Shin GCTS Common Stock Award 1.15% 9,259 814,068 30 Jun 2026 Direct
Jeffrey Tuder GCTS Common Stock Award 20.5% 24,122 141,931 31 Mar 2026 Direct
Kyeongho Lee GCTS Common Stock Award 2.27% 24,122 1,086,863 31 Mar 2026 Direct
Nelson Chan GCTS Common Stock Award 23.8% 24,122 125,642 31 Mar 2026 Direct
Kukjin Chun GCTS Common Stock Award 37% 24,122 89,377 31 Mar 2026 Direct
Robert Barker GCTS Common Stock Award 20.4% 24,122 142,451 31 Mar 2026 Direct
Hyunsoo Shin GCTS Common Stock Award 3.09% 24,122 804,809 31 Mar 2026 Direct
Kukjin Chun GCTS Common Stock Gift -38% -40,000 65,255 23 Feb 2026 Direct
Jeffrey Tuder GCTS Common Stock Award 24.2% 22,916 117,809 31 Dec 2025 Direct
Robert Barker GCTS Common Stock Award 24% 22,916 118,329 31 Dec 2025 Direct
Nelson Chan GCTS Common Stock Award 29.2% 22,916 101,520 31 Dec 2025 Direct
Kukjin Chun GCTS Common Stock Award 27.8% 22,916 105,255 31 Dec 2025 Direct
Kyeongho Lee GCTS Common Stock Award 2.2% 22,916 1,062,741 31 Dec 2025 Direct
Hyunsoo Shin GCTS Common Stock Award 3.02% 22,916 780,687 31 Dec 2025 Direct
Hyunsoo Shin GCTS Common Stock Purchase 2.26% $21,408 $1.28 16,725 757,771 25 Nov 2025 Direct
Hyunsoo Shin GCTS Common Stock Purchase 0.43% $4,070 $1.28 3,180 741,046 21 Nov 2025 Direct
Hyunsoo Shin GCTS Common Stock Purchase 3.57% $32,580 $1.28 25,453 737,866 20 Nov 2025 Direct
Jeffrey Tuder GCTS Common Stock Award 23.6% 18,092 94,893 30 Sep 2025 Direct
Hyunsoo Shin GCTS Common Stock Award 2.61% 18,092 712,413 30 Sep 2025 Direct
Kyeongho Lee GCTS Common Stock Award 1.77% 18,092 1,039,825 30 Sep 2025 Direct
Kukjin Chun GCTS Common Stock Award 28.2% 18,092 82,339 30 Sep 2025 Direct
Nelson Chan GCTS Common Stock Award 29.9% 18,092 78,604 30 Sep 2025 Direct
Robert Barker GCTS Common Stock Award 23.4% 18,092 95,413 30 Sep 2025 Direct
John Schlaefer GCTS Common Stock, par value $0.0001 per share Other 0.27% 555 202,728 26 Sep 2025 Direct
Jeemee Kim GCTS Common Stock, par value $0.0001 per share Award 32.9% 75,000 302,701 19 Sep 2025 Direct
John Schlaefer GCTS Common Stock, par value $0.0001 per share Award 59% 75,000 202,173 19 Sep 2025 Direct
Edmond Cheng GCTS Common Stock, par value $0.0001 per share Award 98.7% 75,000 151,000 19 Sep 2025 Direct
Alex Sum GCTS Common Stock, par value $0.0001 per share Award 69% 75,000 183,743 19 Sep 2025 Direct
Hyunsoo Shin GCTS Common Stock Purchase 6.78% $66,541 $1.51 44,067 694,321 12 Sep 2025 Direct
Hyunsoo Shin GCTS Common Stock Purchase 1.61% $13,390 $1.30 10,300 650,254 05 Sep 2025 Direct
Hyunsoo Shin GCTS Common Stock Purchase 1.31% $10,395 $1.26 8,250 639,954 04 Sep 2025 Direct
Hyunsoo Shin GCTS Common Stock Purchase 23.7% $152,460 $1.26 121,000 631,704 15 Aug 2025 Direct
* marks a reported price that did not pass the local price check.
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