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Monolithic Power Systems

MPWR on Nasdaq. Monolithic Power Systems sells power management chips to electronics makers. Market value $72.7bn.

Watch this stockFree. We tell you when something changes.

Price checks use the past 12 months to June 2026. Quality checks use five annual reports, the latest for the year to December 2025.

We can't read total debt from the filing, so debt is left out.

Should I look at this?

Look carefully before going further

Why it could be worth it

What to watch out for

Read the warning sign in its own filings

This is not advice. Check the numbers below.

Compare with another stock

Cash yield
past 12 months to June 2026
0.8%low

For every $100 of what the whole company costs, it produced $0.81 of spare cash in the past 12 months. A savings account pays about $4.

Price to profit
past 12 months to June 2026
n/a

The filings do not give us enough to work this out.

Return on capital
five annual reports to December 2025
n/a

The filings do not give us enough to work this out.

Quality score: 80 of 100. Price score: 27 of 100. Our list needs 70 on quality and 60 on price.

$1,473.69 a share, 77% above its 1-year low

Over the past year the price has ranged from $833.18 to $1,714.09.

Dividend: 0.4% a year

Paid every year for at least 5 years

Payouts have jumped around in recent years, so this may not repeat.

Prices from Tuesday’s close (6 October).

Five years of cash, in billions

0.2
0.2
0.6
0.6
0.7
0.6
2021202220232024202512 monthsto Jun '26
Revenue
$1.2bn$1.8bn$1.8bn$2.2bn$2.8bn
Operating margin
21.7%29.4%26.5%24.4%26.1%
Debt to equity
n/an/an/an/an/a
Shares outstanding
0.05bn0.05bn0.05bn0.05bn0.05bn

Health checks

  • Free cash flow positive5 of 5 years
  • Accounting looks honest (Beneish)Not enough data
  • Financial strength (Piotroski)6 of 8 checks we could run
  • Profit backed by cash (accruals)Yes
  • DebtUnknown
  • Revenue growth, five yearsStrong, 27.0% a year
  • Buying back its own sharesRoughly flat

The quarter to June 2026

How the business did, compared with the same quarter a year earlier.

  • Sales: $981 million last quarter, up 48% on a year ago.
  • Profit: $257 million, up 91% on a year ago.
  • It keeps 29 cents of each $1 of sales as operating profit, up from 26 cents a year earlier.
  • Spare cash over the past 12 months: $586 million, down from $706 million.
  • 3% more shares than a year ago. Each share owns a bit less of the company.
  • Sales grew on a year ago in each of the last 4 quarters.
Sales by quarter
Sales by quarter
Quarter toAmount
September 2024$620m
December 2024$622m
March 2025$638m
June 2025$665m
September 2025$737m
December 2025$751m
March 2026$804m
June 2026$981m
Profit by quarter
Profit by quarter
Quarter toAmount
September 2024$144m
December 2024$1.3bn
March 2025$135m
June 2025$135m
September 2025$180m
December 2025Not reported
March 2026$193m
June 2026$257m

From the company's quarterly reports to the SEC.

Dates

Next results (estimated)
29 October 2026
Last annual report (10-K)
27 February 2026
Next quarterly (estimated, 10-Q)
4 November 2026

Who owns it

3 long-term investors we follow own it, unchanged from 3 last quarter. 1,240 funds in all.

Jun '25
Dec '25
Jun '26
Largest holders overall

From 13F filings for the quarter ended 30 June 2026.

Big holders and activists

5 investors own more than 5%.

From Schedule 13D and 13G filings: anyone owning more than 5% must file one.

What insiders did

No insider bought shares on the open market in the last 12 months. 11 sold $746m, $277m of it under preset trading plans.

  • Hsing Michael
    CEO, Director
    Sold
    under a preset trading plan
    Date
    28 September 2026
    Shares
    30,000
    Price
    $1344.97
    Value
    $40m
  • DEAN ROBERT W II
    Interim CFO
    Sold
    Date
    24 August 2026
    Shares
    32
    Price
    $1297.72
    Value
    $41,527
  • CHANG KUO WEI HERBERT
    Director
    Sold
    Date
    24 August 2026
    Shares
    50
    Price
    $1281.57
    Value
    $64,079
  • DEAN ROBERT W II
    Interim CFO
    Sold
    Date
    17 August 2026
    Shares
    6
    Price
    $1413.64
    Value
    $8,482
  • CHANG KUO WEI HERBERT
    Director
    Sold
    Date
    11 August 2026
    Shares
    50
    Price
    $1420.00
    Value
    $71,000
  • DEAN ROBERT W II
    Interim CFO
    Sold
    Date
    5 August 2026
    Shares
    105
    Price
    $1344.27
    Value
    $141,148
  • Sciammas Maurice
    EVP, WW Sales & Marketing
    Sold
    under a preset trading plan
    Date
    3 August 2026
    Shares
    30
    Price
    $1343.94
    Value
    $40,318
  • Sciammas Maurice
    EVP, WW Sales & Marketing
    Sold
    under a preset trading plan
    Date
    15 July 2026
    Shares
    15,000
    Price
    $1349.73
    Value
    $20m
  • Sciammas Maurice
    EVP, WW Sales & Marketing
    Sold
    under a preset trading plan
    Date
    1 July 2026
    Shares
    30
    Price
    $1351.61
    Value
    $40,548
  • Sciammas Maurice
    EVP, WW Sales & Marketing
    Sold
    under a preset trading plan
    Date
    1 June 2026
    Shares
    30
    Price
    $1533.95
    Value
    $46,019

From Form 4 filings: insiders must report trades in their own company's shares within two days.

Warning signs in its filings

Problems the company itself reported to the SEC, in its own words.

2 serious warning signs in Monolithic Power Systems’ filings.

We look for five warning signs: doubt it can keep going, weak checks on its own accounts, a notice that its past accounts can't be relied on, a change of auditor, and one customer bringing in a big share of sales. We don't check lawsuits, investigations or debt yet.

We checked the auditor's report, internal controls, restatement notices, auditor changes and big customers in the 10-K filed 27 Feb 2026, plus the 10-Q filed 5 Aug 2026 and 4 later 8-Ks.

  • Weak checks on its own accounts

    Serious

    The company said its checks on its own accounts did not work at the end of its latest quarter. Mistakes could slip into the numbers.

    “Based on this evaluation, and due to the finding of the material weakness described below, our Chief Executive Officer and Interim Chief Financial Officer concluded that, as of June 30, 2026, our disclosure controls and procedures were not effective to provide reasonable assurance that information we are required to disclose in reports that we file or submit under the Exchange Act is recorded, processed, summarized, and reported within the time periods specified in the SEC’s rules and forms.”

    From the 10-Q filed 5 August 2026, Part I, Item 4. Controls and Procedures. Read it in the filing

  • Its past accounts can't be relied on

    Serious

    It told the SEC its earlier accounts should no longer be relied on, usually because they contained errors.

    8-K Item 4.02 filed 27 Feb 2026: the company said its earlier financial statements should no longer be relied on.

    From an 8-K filed 27 February 2026: Previously issued accounts should no longer be relied on. Open the filing

  • One big customer

    Worth knowing

    One customer brings in a big share of sales: 26% last year. Losing that customer would hurt.

    “In 2025, three distributors accounted for 26%, 18% and 10% of our total revenue.”

    From the 10-K filed 27 February 2026, Item 1. Business. Read it in the filing

A 10-K is the yearly report every US company files with the SEC. An 8-K is a short notice of a big event.

What could go wrong

Cheap for a reason is the question the numbers cannot answer.

Whether the price already reflects the risks is what the deep dive is for.

The deep dive

Everything above is arithmetic on public filings. The deep dive reads the last ten years of annual reports, the proxy statements, and the earnings calls, then argues the case the way Buffett, Klarman, and Hohn would, and checks every claim against the source.

  • What the business is worth, as a range, and the margin of safety at today’s price
  • Prices to start buying, buy, and buy hard
  • The three things that would make this a mistake
  • Every number footnoted to the filing it came from
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What a finished deep dive looks like

Not advice. Numbers on this page come from SEC filings and are updated each night; prices are updated again after the US market closes. The five-year figures are rounded.