About 0.3% overall. As a group they still hold 99.7% of their starting shares. These figures leave out Charles Liang, the largest holder (reports the same shares as Sara Liu, where they are counted).
No officer or director trades were reported for the past 30 days. The most recent before that:
| Who | Shares | Price | % of total stake | Total stake after | Trade date | Filed |
|---|---|---|---|---|---|---|
| Sara Liu Director Also reported by spouse Charles Liang | 100,000 | $40.00 | 0.2% | 66.20M | Sep 4, 2026 | Sep 8, 2026 |
"% of total stake" is the shares in this event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings don't reconcile, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.
Percentages cover 14 of 16 officers and directors. Left out: Charles Liang (reports the same shares as Sara Liu, where they are counted); George Kao (most of their shares vested during the period, so a percentage would mislead). Disclosed company stock is not an insider's whole wealth.
Officers and directors, past 12 months. Each bar is the insider's vested stake at the start of the period (Oct 8, 2025). The gold part is what they sold.
Officers and directors, Oct 2025 to Oct 2026. Each sale is counted once: under a disclosed plan, else to cover taxes, else no plan disclosed.
No. Charles Liang reported no open-market sales in the past 12 months.
Filings rarely give a reason, and we don't guess at one. What they show is how the sales were made: 69% of sales by value ran under 10b5-1 trading plans disclosed in the filings and 31% had no disclosed plan. A trading plan schedules sales in advance.
No. Officers and directors reported no purchases in the past 12 months.
About 0.3% overall. As a group they still hold 99.7% of their starting shares. These figures leave out Charles Liang, the largest holder (reports the same shares as Sara Liu, where they are counted). That covers the 12 months to Oct 8, 2026 and counts vested shares reported on SEC Forms 3, 4 and 5, which is not an insider's whole wealth.
| Who sold | Amount | % of holdings | Trading plan |
|---|---|---|---|
| Sara Liu Director Also reported by spouse Charles Liang, President and CEO | $7.7M 200K shares | 0.3% | Disclosed plan |
| George Kao SVP, Operations | $1.9M 57K shares | 30%†i† Most of the shares George Kao sold arrived during the period, so this is shares sold as a share of the 22K held at the start plus the 175K received, less 5.3K withheld by the company for taxes. | No plan disclosed |
| Sherman Tuan Director | $1.6M 49K shares | 19% | No plan disclosed |
Vested shares across all share classes, held directly and through trusts, LLCs and family members, as reported on SEC Forms 3, 4 and 5. Unvested awards and options are never counted as owned shares.
| Insider | Held Oct 8, 2025 | Sold | Held Oct 8, 2026 | Still held | ||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Charles LiangiAdditional holdings last reported more than 3 years ago are shown separately and excluded from totals. Sales of 200,000 shares are also reported by Sara Liu (spouse); they are counted once, under Sara Liu. President and CEO, Director | Same 66.20M shares as Sara Liu; counted there | |||||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Charles Liang+49Kshares vested or exercised −345Kgifted (net of own trusts) −16Kwithheld by the company for taxes 41K → 20Kunvested awards, start → end
Additional holdings last reported Feb 10, 2022, not confirmed since: 14,181,350 shares. Not included in any total or percentage on this page.
Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
Sara LiuiAdditional holdings last reported more than 3 years ago are shown separately and excluded from totals. Sales of 200,000 shares are also reported by Charles Liang (spouse); they are counted once, here. Director Shares also reported by spouse Charles Liang | 66.71M | −200K | 66.20M | 99% | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Sara LiuName on SEC filings: Liang Liu (Liu Liang Chiu-Chu Sara). +49Kshares vested or exercised −345Kgifted (net of own trusts) −16Kwithheld by the company for taxes 41K → 20Kunvested awards, start → end
Additional holdings last reported Feb 10, 2022, not confirmed since: 14,181,350 shares. Not included in any total or percentage on this page.
Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
Yih-Shyan LiawiMinor difference of 193,770 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer). Additional holdings last reported more than 3 years ago are shown separately and excluded from totals. New Form 3 filed 2023-12-14; earlier filings set aside. Director | 15.26M | 0 | 15.47M | no sales | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Yih-Shyan Liaw+30Kshares vested or exercised 0gifted (net of own trusts) −14Kwithheld by the company for taxes 63K → 39Kunvested awards, start → end
Additional holdings last reported May 31, 2011, not confirmed since: 12,000,000 shares. Not included in any total or percentage on this page.
Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. Reconciliation: minor difference of 193,770 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer). | ||||||||||||||||||||||||||||||||||||||||
| Tally Liu Director | 285K | 0 | 289K | no sales | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Tally Liu+3.4Kshares vested or exercised 0gifted (net of own trusts) 3.4K → 3.9Kunvested awards, start → end Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
| Sherman Tuan Director | 256K | −49K | 207K | 81% | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Sherman Tuan0shares vested or exercised 0gifted (net of own trusts) none reportedunvested awards, start → end Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
Jin XiaoiStarted reporting during the period; starting holdings are from the Form 3. Sr. Corporate VP, Engineering | 183K | 0 | 195K | no sales | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Jin Xiao+19Kshares vested or exercised 0gifted (net of own trusts) −7Kwithheld by the company for taxes 28K → 19Kunvested awards, start → end
Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
| David Weigand SVP, Chief Financial Officer | 100K | 0 | 135K | no sales | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for David Weigand+65Kshares vested or exercised 0gifted (net of own trusts) −30Kwithheld by the company for taxes 73K → 69Kunvested awards, start → end Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
| Kenneth Cheung SVP, Chief Accounting Officer | 56K | 0 | 64K | no sales | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Kenneth Cheung+13Kshares vested or exercised 0gifted (net of own trusts) −5Kwithheld by the company for taxes 24K → 15Kunvested awards, start → end Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
| Judy Lin Director | 55K | 0 | 60K | no sales | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Judy Lin+5.4Kshares vested or exercised 0gifted (net of own trusts) 5.4K → 7.9Kunvested awards, start → end Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
| Don Clegg SVP, Worldwide Sales | 43K | 0 | 51K | no sales | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Don Clegg+15Kshares vested or exercised 0gifted (net of own trusts) −6.7Kwithheld by the company for taxes 43K → 37Kunvested awards, start → end Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
Vikranth MalyalaiStarted reporting during the period; starting holdings are from the Form 3. SVP, Chief Business Officer | 35K | 0 | 48K | no sales | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Vikranth Malyala+24Kshares vested or exercised 0gifted (net of own trusts) −11Kwithheld by the company for taxes 41K → 40Kunvested awards, start → end
Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
| George Kao SVP, Operations | 22K | −57K | 135K | not meaningful | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for George Kao+175Kshares vested or exercised 0gifted (net of own trusts) −5.3Kwithheld by the company for taxes 32K → 21Kunvested awards, start → end Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
Matthew ThaubergeriStarted reporting during the period; starting holdings are from the Form 3. Chief Revenue Officer | 4.8K | 0 | 6.5K | no sales | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Matthew Thauberger+3.4Kshares vested or exercised 0gifted (net of own trusts) −1.7Kwithheld by the company for taxes 14K → 21Kunvested awards, start → end
Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
| Susan Mogensen Director | 3.3K | 0 | 8.7K | no sales | ||||||||||||||||||||||||||||||||||||
| Scott Angel Director | 1.7K | 0 | 7.1K | no sales | ||||||||||||||||||||||||||||||||||||
| Robert Blair Director | 1.6K | 0 | 7K | no sales | ||||||||||||||||||||||||||||||||||||
Vesting, gifts, unvested awards and holding lines for Robert Blair+5.4Kshares vested or exercised 0gifted (net of own trusts) 5.4K → 7.9Kunvested awards, start → end Stock options (not counted as shares):
Estimate: options held × ($40.00 − strike price), using the most recent insider trade price on Form 4 (Sep 4, 2026), not a market close. | ||||||||||||||||||||||||||||||||||||||||
16 of 16 insiders fully reconciled: starting holdings plus reported transactions match ending holdings (15 exactly, 1 with a minor or footnoted difference). Percentages cover 14 of 16 officers and directors. Left out: Charles Liang (reports the same shares as Sara Liu, where they are counted); George Kao (most of their shares vested during the period, so a percentage would mislead). "Still held" compares ending with starting vested shares; a plus sign means the holding grew.
Officer and director open-market sales: $11.2M across 305,534 shares. Plan status and stated purpose are separate questions, and a sale can have both.
The lighter segment is sales with no plan disclosed in the filing ($3.5M), including tax-related sales outside a plan.
Sales with no 10b5-1 plan and no tax reference in the filing. $1.9M of it is George Kao. No plan disclosed is a statement about the filing, not about why the sale happened. Largest such sale: George Kao, Nov 24, 2025
112,317 shares ($4.1M) were withheld by the company for taxes, which isn't a market sale.
Gifts the filings describe as charitable. Gifts are not sales and are not included in the sale totals.
| Seller | Shares sold | Proceeds | Under a disclosed plan | Share of total | Sales dates |
|---|---|---|---|---|---|
| Sara Liu Director | 200K | $7.7M | 100% | 69% | Sep 3, 2026 to Sep 4, 2026 |
| George Kao SVP, Operations | 57K | $1.9M | 0% | 17% | Nov 24, 2025 to Nov 24, 2025 |
| Sherman Tuan Director | 49K | $1.6M | 0% | 14% | Nov 26, 2025 to Nov 26, 2025 |
| Month | Sale proceeds | Disclosed plan | To cover taxes | No plan disclosed |
|---|---|---|---|---|
| Oct 2025 | $0 | $0 | $0 | $0 |
| Nov 2025 | $3.5M | $0 | $0 | $3.5M |
| Dec 2025 | $0 | $0 | $0 | $0 |
| Jan 2026 | $0 | $0 | $0 | $0 |
| Feb 2026 | $0 | $0 | $0 | $0 |
| Mar 2026 | $0 | $0 | $0 | $0 |
| Apr 2026 | $0 | $0 | $0 | $0 |
| May 2026 | $0 | $0 | $0 | $0 |
| Jun 2026 | $0 | $0 | $0 | $0 |
| Jul 2026 | $0 | $0 | $0 | $0 |
| Aug 2026 | $0 | $0 | $0 | $0 |
| Sep 2026 | $7.7M | $7.7M | $0 | $0 |
| Oct 2026 | $0 | $0 | $0 | $0 |
Less than usual: about one-seventh of the 5-year average. 3 insiders sold; the average is 6 a year.
| 12 months ending | Shares sold | Insiders who sold | Proceeds |
|---|---|---|---|
| Oct 8, 2026 Latest 12 months | 306K | 3 | $11.2M |
| Oct 8, 2025 1 year earlier | 1.04M | 5 | $50.1M |
| Oct 8, 2024 2 years earlier | 1.55M | 9 | $64.1M |
| Oct 9, 2023 3 years earlier | 2.74M | 7 | $32.8M |
| Oct 9, 2022 4 years earlier | 1.60M | 3 | $6.9M |
| Oct 9, 2021 5 years earlier | 3.58M | 5 | $12.9M |
Open-market sales (Form 4 code S) by people who were officers or directors, in split-adjusted shares. Earlier years include people who have since left. A sale that an outside holder also reports (a family trust, a fund) is counted with outside holders in every year. Shares, not dollars, are compared, so a change in the stock price doesn't look like a change in selling. Years the filings don't fully cover are shown but left out of the average.
Every officer and director reconciles for this period.
Yih-Shyan Liaw: minor difference of 193,770 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).
External context: we only cite outside events when a documented connection exists. None is shown for this period.
All 1,013 Forms 3, 4 and 5 filed for Supermicro (SEC CIK 1375365) from Mar 28, 2007 to Sep 8, 2026, retrieved from SEC EDGAR on Oct 8, 2026. Prices are the ones reported in each filing, often weighted averages.
Probable 10-for-1 stock split on or before Oct 1, 2024 (split date stated in a footnote). Splits aren't reported as transactions; 14 holding lines changed by exactly this ratio, so earlier share counts are restated.
Holdings. Each holding line (a share class plus an owner, such as a trust or LLC) carries its last reported balance forward. Entities first reported during the period start at zero, so transfers between an insider's own trusts don't count as selling. Lines not reported for three years or more are listed separately and left out of totals.
Sales. A sale counts as under a 10b5-1 plan if its footnote cites one or the filing's Rule 10b5-1 box is checked, and as tax-related if its footnote cites tax obligations or sell-to-cover. Shares withheld by the company for taxes are listed separately. Sales with neither attribute are labeled "no plan disclosed".
| Name | Last filed | Last reported balance |
|---|---|---|
| Daniel Fairfax | Aug 13, 2024 | 198,330 shares, last reported balance as of Aug 9, 2024 |
| Shiu Chan | Feb 5, 2024 | 429,170 shares, last reported balance as of Feb 1, 2024 |
| Saria Tseng | Aug 5, 2021 | 298,890 shares, last reported balance as of Jun 30, 2021 |
| Hwei-Ming Tsai | May 12, 2021 | 5,586,000 shares, last reported balance as of May 10, 2021 |
| Michael McAndrews | May 12, 2021 | 216,000 shares, last reported balance as of May 10, 2021 |
| Alex Hsu | Feb 18, 2021 | 23,940 shares, last reported balance as of Feb 16, 2021 |
| Kevin Bauer | Nov 18, 2020 | 88,450 shares, last reported balance as of Nov 16, 2020 |
| Howard Hideshima | Nov 27, 2017 | 12,200 shares, last reported balance as of Nov 22, 2017 |
| Cheng-Hsien Chou | Nov 14, 2017 | 15,600 shares, last reported balance as of Nov 10, 2017 |
| Laura Black | Mar 3, 2017 | No balance on record |
| Gregory Hinckley | Feb 12, 2015 | No balance on record |
| Edward Hayes Jr. | Feb 10, 2012 | No balance on record |
| Bruce Alexander | Apr 30, 2007 | No balance on record |