Key points
- Amkor director Guillaume Rutten has filed five SEC notices in 2026 covering 130,000 shares, $7.9 million combined.
- Only his February 17 sale, 10,000 shares, came from a 10b5-1 trading plan. The other four were his own call.
- Four more Amkor insiders sold stock in May and June on their own timing too, while AMKR fell 41% from its 6-month high.
- General counsel Mark Rogers sells about 5,000 shares almost every month on a plan adopted in August 2025, the one Amkor insider selling on autopilot.
A Form 144 was filed with the SEC on Thursday by Guillaume Rutten, a director at Amkor Technology (AMKR) in Tempe, Arizona. It covers 25,000 shares worth $1,362,608, to be sold on or after August 6 through Morgan Stanley Smith Barney. Taken alone, it's an ordinary notice. What made me look twice is that it's Rutten's second Form 144 in two days, and his fifth SEC filing of the year.
Add those five together and they cover 130,000 shares. That's $7.9 million combined in one calendar year, real money for one director. What made me want to write about it is the box on each filing that says whether the sale was scheduled months in advance. Only one of the five checks it.
| Filed | Type | Shares | Value | Plan on file? |
|---|---|---|---|---|
| Feb 17 | Form 4 | 10,000 | $458,900 | Yes, adopted Jun 6, 2025 |
| Feb 24 | Form 4 | 20,000 | $976,000 | No |
| May 8 | Form 4 | 50,000 | $3,713,965 | No |
| Aug 5 | Form 144 | 25,000 | $1,383,765 | No |
| Aug 6 | Form 144 | 25,000 | $1,362,608 | No |
A Form 144 is a notice of intent, filed before any shares actually move. It tells a broker to go ahead, and the actual amount sold can land smaller than what's filed, or fall through completely. The two August filings are still open. They're pending until a matching Form 4 confirms them, and the February and May rows already report completed trades.
One of five came with a plan attached
One footnote sets Rutten's February 17 sale apart from the rest. It reads: "The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 06, 2025." The language is the SEC's own, describing a sale scheduled in advance. It's a plan an insider adopts during an open trading window, then lets run untouched on its own calendar.
Rutten's other four filings all leave that field blank. The 20,000 shares he sold a week later, on February 24. The 50,000 he sold in May. The 50,000 he's now filed to sell in August, split across two consecutive days. A blank plan field means something specific under the SEC's own instructions. The filer picked that sale's timing on their own, this time, instead of locking it in months earlier.
A blank box is common enough on its own. It's legal too. Directors sell for all kinds of personal reasons unrelated to the company, a tax bill or a house purchase among them. Sometimes it's plain diversification, when too much of someone's net worth sits in one stock. What the box does tell you is timing. A director on a plan picked the date before he knew what the stock would be doing that week. A director selling on his own call picked it this week, on purpose, at a price he could see.
The rest of Amkor's board picks its own days too
Four other Amkor insiders sold stock since May, each one on their own timing. Winston Churchill and Douglas Alexander are both directors. They sold on the same day, May 5, within thirty cents of the same $76 share price. So did Roger Carolin, a third director. He sold the most of the three, 20,000 shares to Churchill's 7,000 and Alexander's 5,000. Gil Tily, a fourth director, sold 15,000 shares six days later at $77.30. Churchill sold again on June 12. Chief executive Kevin Engel sold twice this year on his own timing too, in February and again on July 30.
One Amkor insider at the company has the opposite pattern. General counsel Mark Rogers has filed a Form 144 and a matching Form 4 almost every month since last August. It's always around 5,000 shares, always tied to a plan he adopted August 1, 2025. His filings this year have landed in the same three-day window every month, the 16th through the 20th. It's the cleanest kind of insider selling there is, scheduled so far ahead that the calendar alone decides when he sells.
All of this discretionary selling has run into a falling stock. AMKR's high over the past six months is $93.55. It closed at $54.16 Thursday and traded near $55.23 midday Friday, down 41 percent from that high and about 28 percent from where the May 5 sellers got out.
Rutten's own stake in the company gives some sense of scale. His last reported direct holding was 511,732 shares, as of a June 30 filing. That's worth about $28.3 million at Friday's price. If both August notices are completed in full, that would take him to roughly 461,732 shares, a reduction of about 10 percent from where he stood before them.
The public record stops at the trade itself, leaving the motive an open question, for Rutten and for the four other directors who sold on their own timing while the stock was still near its highs. Amkor's business sits inside a real growth story of its own. We covered the advanced-packaging bottleneck the company works in here, and how prescheduled trading plans actually work in a separate piece. Our insider tracker flags a blank plan box the same way on every filing it sees, and Amkor's own filings land on its filings page as they arrive. The Forms 4 confirming this week's two notices are due within two business days of whenever Rutten actually sells.
Sources
- SEC Form 144 for Guillaume Marie Jean Rutten, Amkor Technology, filed August 6, 2026 (accession 0001950047-26-007737), $1,362,607.50 for 25,000 shares
- SEC Form 144 for Rutten filed August 5, 2026 (accession 0001950047-26-007683), $1,383,765 for 25,000 shares, and its record of his May 8 sale
- SEC Form 4 for Rutten filed February 18, 2026 (accession 0001628280-26-009053), reporting the February 17 sale under a Rule 10b5-1 plan adopted June 6, 2025
- SEC Forms 4 for Rutten filed February 26 and May 12, 2026 (accessions 0001628280-26-012300 and 0001628280-26-034167), reporting the February 24 and May 8 sales
- SEC Forms 4 for Winston Churchill, Douglas Alexander, Roger Carolin, Gil Tily and Kevin Engel, filed May and June 2026
- SEC Form 144 and Form 4 for Mark N. Rogers filed July 16 and July 20, 2026 (accessions 0001950047-26-007148 and 0001628280-26-048825), and his prior monthly filings since August 2025
- Amkor Technology (AMKR) daily closing prices, six months to August 7, 2026
