Total buying$00 buys
MPWR
MONOLITHIC POWER SYSTEMS, INC.
NasdaqTechnologySemiconductors & Related Devices
Insider activity for last month from 09/19 to 10/19.
How these metrics are calculated
Counts use processed Form 4 rows. Purchase and sale metrics use codes P and S; totals remain unknown when any matching value is missing. Rows without a usable transaction date cannot be assigned to a rolling period and are excluded.
Total selling$40.3M8 sells
Net open-market−$40.3MBuying minus selling
Active insiders1Distinct reporting owners
Insider activity report
Calendar-month buckets within the selected date range
Latest filing: Sep 30, 2026
Open-market transaction mix · 8 transactions in the selected period
Code A includes awards, grants and other acquisitions; these are not open-market buys. A rolling period can include partial calendar months.
View exact monthly counts and disclosed values
| Month | Buys | Sells | Awards (A) | Buy value | Sell value | Net P/S value |
|---|---|---|---|---|---|---|
| Sep 2026 | 0 | 8 | 0 | $0 | $40.3M | -$40.3M |
| Oct 2026 | 0 | 0 | 0 | $0 | $0 | $0 |
Distinct insiders active
Reporting-owner CIKs by month · peak Sep 2026 (1)Sep 2026Oct 2026
Largest insider activity
By absolute net disclosed value · current transaction page- HM-$40.3M
MPWR transaction history
Newest filings · 20 transactions per pageLatest insider transactions
Form 4 filings from last month.| Company | Insider | Activity | Disclosed value | Filed (ET) |
|---|---|---|---|---|
MPWRMONOLITHIC POWER SYSTEMS, INC. | Hsing MichaelCEO | S · sale10b5-1 detectedSEC filing ↗ | -$176kView disclosure → | |
MPWRMONOLITHIC POWER SYSTEMS, INC. | Hsing MichaelCEO | S · sale10b5-1 detectedSEC filing ↗ | -$14.8MView disclosure → | |
MPWRMONOLITHIC POWER SYSTEMS, INC. | Hsing MichaelCEO | S · sale10b5-1 detectedSEC filing ↗ | -$8.54MView disclosure → | |
MPWRMONOLITHIC POWER SYSTEMS, INC. | Hsing MichaelCEO | S · sale10b5-1 detectedSEC filing ↗ | -$7.77MView disclosure → | |
MPWRMONOLITHIC POWER SYSTEMS, INC. | Hsing MichaelCEO | S · sale10b5-1 detectedSEC filing ↗ | -$3.94MView disclosure → | |
MPWRMONOLITHIC POWER SYSTEMS, INC. | Hsing MichaelCEO | S · sale10b5-1 detectedSEC filing ↗ | -$1.48MView disclosure → | |
MPWRMONOLITHIC POWER SYSTEMS, INC. | Hsing MichaelCEO | S · sale10b5-1 detectedSEC filing ↗ | -$2.81MView disclosure → | |
MPWRMONOLITHIC POWER SYSTEMS, INC. | Hsing MichaelCEO | S · sale10b5-1 detectedSEC filing ↗ | -$788kView disclosure → |
Filing-only signals
Deterministic matches in the selected period
Filing detail checks
Secondary metrics for the selected periodTransaction codes
By Form 4 transaction code in selected period8transactionstxns
- S · Open-market sells · dominant8 · 100%
Activity by reported role
A joint filing can contribute to multiple rolesChief executive officer8
Reported Holdings After
Separated by insider, security, and ownership type
Hsing MichaelCommon Stock · Direct
818,264Sep 28, 2026
These are reported post-transaction holdings, not company-wide ownership percentages. Securities, indirect vehicles, and amendments are kept separate.
Filing activity heatmap
Current transaction page only · each cell is a filing date · buys green, sells redSep 19 → Oct 19
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MONOLITHIC POWER SYSTEMS, INC. Insider Activity FAQ
SEC Form 4 contextWho recently reported transactions at MONOLITHIC POWER SYSTEMS, INC.?
Hsing Michael.
When was the latest reported open-market purchase?
No code-P purchase is available for this period.
When was the latest reported open-market sale?
Hsing Michael reported a sale on Sep 28, 2026 valued at $176k. Read the SEC filing.
What is the recent purchase and sale balance?
Net open-market selling in the selected period was $40,349,046.72. Sales can occur for many non-investment reasons.
Where can I see the original SEC filing?
Every transaction row and latest-activity fact links to its original SEC filing.
What do these Form 4 transaction codes mean?
P and S generally describe open-market or private purchases and sales. A, D, F, M, X, G, J, and V describe awards, issuer dispositions, tax withholding, exercises, gifts, other transactions, and voluntary early reports; review each filing and its footnotes for context.