Insider trade

CEO sold ~$8.54M of MPWR shares in the open market

Traded Sep 28, 2026 · Filed Sep 30, 2026

~$8.54M
Reported value · 6,343 sh @ $1,347.15: 829K
Holds after · shares reported: +0.7%
stock since the trade · S&P 500 -0.2%, $1,351.20 → $1,360.97 on Oct 1

Why it stands out

The boss of Monolithic Power Systems sold $8.54M of Monolithic Power Systems shares. It was planned long ago, so it says very little.

Written from the filing's own figures. OQRO describes what was reported and never tells you what to buy or sell

View the official recordSEC Form 4 — Statement of Changes in Beneficial Ownership

All the details

Dates, kept separate

Transaction date: Sep 28, 2026
Reporting period: Not applicable
Filed with the SEC: Sep 30, 2026

CEO$1M+Pre-arranged plan referenced

Context

Classification

open market sale

Code S — open-market or private sale

Absolute commitment

~$8,544,972

Shares × reported transaction price

Timing vs results

60 days after results of Jul 30, 2026

Results dates are the company's own 8-K (Item 2.02). Many companies only let insiders trade in a window after results

Price at the time

Closed at $1,351.20 on Sep 28, 2026, 58% above its 52-week low and 20% below its high, after a 4% drop over the previous 30 trading days

52-week range $856.96 (Nov 18, 2025) to $1,689.89 (Jun 3, 2026), 59% of the way up, from 251 adjusted closes. 30 trading days earlier: $1,402.01 on Aug 14, 2026. Describes the past only, not a forecast

Planned / mechanical clue

Footnote references a pre-arranged trading plan (Rule 10b5-1)

Only flagged when a footnote says so; never inferred

Securities lawsuit open at the trade date

A securities lawsuit naming the company as a defendant was filed on Feb 4, 2025 in the U.S. District Court, W.D. Washington. A filing is an allegation, not a finding.

Waterford Township General Employees Retirement System v. Monolithic Power Systems Inc, docket 2:25-cv-00220, via CourtListener (court records). Nature of suit 850, company named as first defendant

Source receipt

Record ID: 0001214659-26-012375
Filed / recorded: Sep 30, 2026, 9:21 PM UTC
Added to OQRO: Oct 2, 2026, 12:28 PM UTC
Parser: form4-xml-v1
Data quality: Verified: identifiers matched exactly
Issuer: MONOLITHIC POWER SYSTEMS, INC.
Issuer CIK: 1280452
Ticker: MPWR
Reporting person: Michael Hsing
Relationship: Director, Officer
Officer title: CEO
Security: Common Stock
Table: Non-derivative (Table I)
Transaction date: Sep 28, 2026
Transaction code: S
Shares / units: 6,343
Price per share: $1,347.15
Acquired / disposed: Disposed (D)
Shares owned after: 829,361
Ownership form: Direct
Amendment: No

Footnotes from the filing

These transactions were made pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on 05/29/2026.
The price is the weighted average sale price for the transactions reported on this line. The prices for the transactions reported on this line range from $1,345.66 to $1,350.47. The reporting person undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.

Around the same time

CEO sold ~$789K of Monolithic Power Systems

Scheduled in advance5d ago

CEO sold ~$2.82M of Monolithic Power Systems

Scheduled in advance5d ago

CEO sold ~$1.48M of Monolithic Power Systems

Scheduled in advance5d ago

Why it stands out

Dates, kept separate

Context

Source receipt

Footnotes from the filing

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