XOOMAR

MONOLITHIC POWER SYSTEMS, INC. (MPWR)

Every FINRA and SEC series the site collects for MONOLITHIC POWER SYSTEMS, INC.: short interest with days to cover, daily short sale volume, fails to deliver and Form 4 insider trades. Listed on Nasdaq, classified by the SEC as semiconductors & related devices.

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1.8M

Short interest

settlement 2026-08-14

2.7

Days to cover

-13.3% vs prior

53.7%

Short share of volume

2026-09-11

41

Fails to deliver

settlement 2026-08-13

-$367K

Insider flow, 90 days

0 buys, 6 sells

As of 2026-09-11.

Short interest

FINRA, twice a month; the last 12 months shown, all 48 settlements in the JSON

As of 14 August 2026, short interest in MPWR is 1,839,078 shares, down 617,877 shares over the last month. Over the last 48 readings it ranged from 1,291,726 shares (15 October 2024) to 2,855,358 shares (31 December 2025). At the reported average volume of 673K shares a day that is 2.7 days to cover.

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SettlementShares shortChangeAvg daily volumeDays to cover
2026-08-141,839,078-13.3%672,5612.73
2026-07-312,122,311-13.6%997,5002.13
2026-07-152,456,955+11.0%919,2742.67
2026-06-302,214,362-5.7%1,475,6391.50
2026-06-152,348,322+1.2%772,0173.04
2026-05-292,319,453+17.4%709,7013.27
2026-05-151,975,414+14.8%643,8253.07
2026-04-301,720,835-5.7%622,8342.76
2026-04-151,825,570-8.1%539,0703.39
2026-03-311,985,296-0.1%536,0743.70
2026-03-131,987,899-3.2%564,4353.52
2026-02-272,054,245-2.2%452,0074.54
2026-02-132,099,811-8.9%844,0532.49
2026-01-302,304,227-0.4%615,5533.74
2026-01-152,313,245-19.0%522,0964.43
2025-12-312,855,358+65.0%917,7223.11
2025-12-151,729,984-6.5%523,4433.31
2025-11-281,850,349+3.0%732,8792.52
2025-11-141,796,489+7.7%663,5692.71
2025-10-311,667,795-11.4%684,8452.44
2025-10-151,881,672-8.3%567,8433.31
2025-09-302,051,204+26.7%502,0604.09
2025-09-151,619,039-15.7%464,0483.49
2025-08-291,920,230-17.2%483,3973.97

Daily short volume

FINRA Reg SHO, last 60 sessions. JSON

As of 11 September 2026, the short share of MPWR volume is 53.7%, up 15.6 points over the last five sessions. Over the last 52 readings it ranged from 26.7% (31 August 2026) to 63.8% (23 July 2026). The latest reading is 7.3 points above the 30-session average of 46.5%, on 152K shares reported.

DateShort volumeTotal volumeShort shareExempt
2026-09-1182K152K53.7%89
2026-09-1098K173K56.7%1
2026-09-0970K150K46.8%55
2026-09-0894K235K39.8%2
2026-09-0482K207K39.7%105
2026-09-0356K148K38.1%11
2026-09-0263K150K42.0%511
2026-09-01111K239K46.3%24
2026-08-3138K142K26.7%2
2026-08-2864K150K42.4%37
2026-08-2771K126K56.2%22
2026-08-2646K99K46.4%0
2026-08-2563K127K49.4%48
2026-08-24127K274K46.1%148
2026-08-2156K159K35.1%955
2026-08-2051K110K46.1%1
2026-08-19100K209K47.7%1,315
2026-08-18191K308K62.1%52
2026-08-1779K132K60.1%145
2026-08-1485K151K56.2%647
2026-08-1368K136K49.6%22
2026-08-1267K139K48.3%23
2026-08-1153K148K36.0%1
2026-08-1079K133K59.7%51
2026-08-0766K185K35.9%56
2026-08-0684K192K43.4%10
2026-08-05133K226K58.8%116
2026-08-04153K392K39.0%95
2026-08-03176K443K39.6%19
2026-07-31311K673K46.1%296

Fails to deliver

SEC, by settlement date. JSON

As of 13 August 2026, the fails-to-deliver balance in MPWR is 41 shares, up 40 shares over the last settlement date. Over the last 52 readings it ranged from 1 share (6 January 2026) to 151,827 shares (29 June 2026). The latest reading sits at the bottom of that range.

SettlementShares failedPriceValue
2026-08-1341$1425.01$58K
2026-08-031$1426.03$1K
2026-07-1738$1305.65$50K
2026-07-10665$1374.13$914K
2026-07-02224$1331.73$298K
2026-07-017,880$1382.36$10.9M
2026-06-307,906$1312.77$10.4M
2026-06-29151,827$1313.32$199.4M
2026-06-2531$1434.95$44K
2026-06-228,983$1563.70$14.0M
2026-06-18214$1448.21$310K
2026-06-1617,033$1652.29$28.1M
2026-06-15155$1577.32$244K
2026-06-123,945$1589.55$6.3M
2026-06-1111,381$1473.04$16.8M
2026-06-09725$1559.18$1.1M
2026-04-24421$1592.17$670K
2026-04-20282$1468.35$414K
2026-04-161,210$1353.00$1.6M
2026-04-151$1363.42$1K
2026-04-107,315$1334.21$9.8M
2026-04-02199$1119.51$223K
2026-04-01242$1093.35$265K
2026-03-31283$1002.34$284K
2026-03-26261$1118.66$292K
2026-03-25600$1101.59$661K
2026-03-24600$1076.35$646K
2026-03-23800$1068.85$855K
2026-03-20147$1092.69$161K
2026-03-1916,276$1075.29$17.5M

Insider trades

SEC Form 4, newest first, 50 of 100 shown. JSON

Insiders at MPWR reported 6 open-market sells worth $367K in the last 90 days and no open-market buys. Sells alone are a weak signal; insiders sell for tax, diversification and estate reasons all the time. Latest filing: Tseng Saria (EVP &amp; General Counsel) on 2026-08-31.

DateInsiderTitleTypeSharesPriceValueOwned after
2026-08-31Tseng SariaEVP &amp; General CounselGift2K$0.00$0142K
2026-08-24DEAN ROBERT W IIInterim CFOJ5$0.00$07K
2026-08-24DEAN ROBERT W IIInterim CFOSell32$1297.72$42K7K
2026-08-24CHANG KUO WEI HERBERTn/aSell50$1281.57$64K515
2026-08-17DEAN ROBERT W IIInterim CFOSell6$1413.64$8K7K
2026-08-11CHANG KUO WEI HERBERTn/aSell50$1420.00$71K565
2026-08-05DEAN ROBERT W IIInterim CFOSell105$1344.27$141K7K
2026-08-04Sciammas MauriceEVP, WW Sales &amp; MarketingGift25K$0.00$0127K
2026-08-03Sciammas MauriceEVP, WW Sales &amp; MarketingSell30$1343.94$40K1K
2026-07-25DEAN ROBERT W IIInterim CFOGrant1K$0.00$07K
2026-06-01Sciammas MauriceEVP, WW Sales &amp; MarketingSell30$1533.95$46K1K
2026-05-29Sciammas MauriceEVP, WW Sales &amp; MarketingGift12K$0.00$013K
2026-05-27Tseng SariaEVP &amp; General CounselSell8K$1700.00$12.9M144K
2026-05-26Zhou Jeffn/aSell486$1680.00$816K4K
2026-05-26DEAN ROBERT W IIInterim CFOSell22$1649.56$36K6K
2026-05-22Tseng SariaEVP &amp; General CounselSell5K$1586.43$7.9M152K
2026-05-22Tseng SariaEVP &amp; General CounselGift200$0.00$0157K
2026-05-18Hsing MichaelCEOSell130$1521.43$198K848K
2026-05-18Hsing MichaelCEOSell352$1518.15$534K848K
2026-05-18Hsing MichaelCEOSell551$1513.11$834K849K
2026-05-18Hsing MichaelCEOSell4K$1507.70$5.7M849K
2026-05-18Hsing MichaelCEOSell3K$1503.05$4.4M853K
2026-05-18Hsing MichaelCEOSell608$1499.46$912K856K
2026-05-18Hsing MichaelCEOSell862$1491.48$1.3M857K
2026-05-18Hsing MichaelCEOSell7K$1486.76$9.9M857K
2026-05-18Hsing MichaelCEOSell6K$1482.51$8.5M864K
2026-05-18Hsing MichaelCEOSell4K$1476.96$6.0M870K
2026-05-18Hsing MichaelCEOSell5K$1472.84$7.4M874K
2026-05-18Hsing MichaelCEOSell6K$1467.62$8.5M879K
2026-05-18Hsing MichaelCEOSell3K$1462.61$5.0M885K
2026-05-18DEAN ROBERT W IIInterim CFOSell4$1563.28$6K6K
2026-05-15Sciammas MauriceEVP, WW Sales &amp; MarketingSell50$1585.51$79K167K
2026-05-15Sciammas MauriceEVP, WW Sales &amp; MarketingSell447$1582.21$707K167K
2026-05-15Sciammas MauriceEVP, WW Sales &amp; MarketingSell703$1577.75$1.1M167K
2026-05-15Sciammas MauriceEVP, WW Sales &amp; MarketingSell1K$1571.49$2.1M168K
2026-05-15Sciammas MauriceEVP, WW Sales &amp; MarketingSell2K$1567.15$3.2M169K
2026-05-15Sciammas MauriceEVP, WW Sales &amp; MarketingSell2K$1562.01$3.1M171K
2026-05-15Sciammas MauriceEVP, WW Sales &amp; MarketingSell2K$1557.48$2.7M173K
2026-05-15Sciammas MauriceEVP, WW Sales &amp; MarketingSell4K$1550.36$5.8M175K
2026-05-13Sciammas MauriceEVP, WW Sales &amp; MarketingGift2K$0.00$025K
2026-05-13DEAN ROBERT W IIInterim CFOJ2K$0.00$06K
2026-05-06Zhou Jeffn/aSell500$1650.00$825K4K
2026-05-06Xiao DemingEVP, Global OperationsSell907$1661.38$1.5M206K
2026-05-06Xiao DemingEVP, Global OperationsSell12K$1657.93$19.2M207K
2026-05-06Xiao DemingEVP, Global OperationsSell14K$1652.80$23.4M218K
2026-05-06Xiao DemingEVP, Global OperationsSell3K$1648.38$5.5M233K
2026-05-06Wynne Eileenn/aSell335$1582.68$530K1K
2026-05-06Elmiger Eugen Jn/aSell514$1600.14$822K5K
2026-05-06Elmiger Eugen Jn/aSell3K$1596.42$4.2M6K
2026-05-06Elmiger Eugen Jn/aSell1K$1591.38$2.2M9K

Form 4 filings are due within two business days of the trade. Insiders sell for many reasons that say nothing about the company; open-market buys are the rarer, stronger signal.

Planned sales (Form 144)

Newest first. JSON

5 Form 144 notices on file for MPWR worth $20.6M at the prices reported; 5 in the last 90 days worth $20.6M. Latest: DEAN ROBERT W II filed on 2026-08-24 to sell 32 shares ($42K) from 2026-08-24.

FiledSellerSharesMarket valueOf outstandingSale fromBroker
2026-08-24DEAN ROBERT W IIOfficer32$42K0.000%2026-08-24Morgan Stanley Smith Barney LLC Executive Financial Services
2026-08-17DEAN ROBERT W IIOfficer6$8K0.000%2026-08-17Morgan Stanley Smith Barney LLC Executive Financial Services
2026-08-11Kuo Wei ChangDirector100$142K0.000%2026-08-11UBS Financial Services Inc
2026-08-05ROBERT DEANOfficer105$141K0.000%2026-08-05Morgan Stanley Smith Barney LLC Executive Financial Services
2026-07-15MAURICE SCIAMMASOfficer15K$20.2M0.031%2026-07-15Morgan Stanley Smith Barney LLC Executive Financial Services

13F holders

Tracked managers holding MPWR at their latest 13F. JSON

9 of the 30 tracked managers held MPWR at their latest 13F, $983.4M in total at quarter-end prices. Citadel Advisors is the largest at $305.5M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 5 added shares and 4 cut.

FundQuarterSharesValueOf portfolioChange in shares
Citadel Advisors2026-06-30221K$305.5M0.03%+121K
Two Sigma Investments2026-06-30196K$270.8M0.20%+175K
Millennium Management2026-06-30174K$240.2M0.09%+161K
Renaissance Technologies2026-06-3063K$87.2M0.12%+55K
D. E. Shaw & Co.2026-06-3029K$40.1M0.02%+3K
AQR Capital Management2026-06-3025K$33.8M0.01%-13K
Bridgewater Associates2026-06-303K$4.3M0.02%-9K
Point72 Asset Management2026-06-30900$1.2M0.00%-900
Fisher Asset Management2026-06-30177$246K0.00%-35

Only the 30 tracked managers on the funds hub; a 13F reports long positions in US listed stock at quarter end, 45 days late, and says nothing about shorts or positions sold since.

Financials

SEC XBRL, as filed. JSON

In Q2 2026 (quarter ended 2026-06-30) MONOLITHIC POWER SYSTEMS, INC. reported revenue of $980.6M, up 47.6% from the same quarter a year earlier, and net income of $257.3M (5.22 diluted EPS). In FY 2025 it generated $838.2M of operating cash flow and spent $6.6M on buybacks and $284.8M on dividends.

Cash
$1.01B
Equity
$3.90B
Total assets
$4.69B
Shares outstanding
49,143,000

Quarterly, last 8 quarters

QuarterPeriod endRevenueNet incomeMarginDiluted EPS
Q2 20262026-06-30$980.6M$257.3M26.2%5.22
Q1 20262026-03-31$804.2M$193.2M24.0%3.92
Q4 2025derived2025-12-31$751.2Mn/an/an/a
Q3 20252025-09-30$737.2M$179.8M24.4%3.74
Q2 20252025-06-30$664.6M$135.0M20.3%2.81
Q1 20252025-03-31$637.6M$135.1M21.2%2.81
Q4 2024derived2024-12-31$621.7Mn/an/an/a
Q3 20242024-09-30$620.1M$144.4M23.3%2.95

Fiscal years, with buybacks and dividends

Fiscal yearEndsRevenueNet incomeOperating cash flowCapexBuybacksDividends
FY 20252025-12-31$2.79Bn/a$838.2M$172.0M$6.6M$284.8M
FY 20242024-12-31$2.21Bn/a$788.4M$146.1M$636.2M$240.6M
FY 20232023-12-31$1.82Bn/a$638.2M$57.6M$3.7M$185.8M
FY 20222022-12-31$1.79Bn/a$246.7M$58.8M$0$138.0M
FY 20212021-12-31$1.21Bn/a$320.0M$94.4M$0$109.4M

Quarters are the three-month figures the company reports; a fourth quarter marked derived is the fiscal year less the three reported quarters, since companies report it only inside the 10-K. Fiscal years are the annual figures. Buybacks are cash paid to repurchase common stock in the year (XBRL PaymentsForRepurchaseOfCommonStock), not authorizations. Balance sheet lines are as of 2026-06-30; shares outstanding as of 2026-07-29 from the cover page.

What this page is

MONOLITHIC POWER SYSTEMS, INC. in the regulatory record

Regulators publish company data in separate files that never sit next to each other: FINRA's twice-monthly short interest, its daily short sale volume, the SEC's fails-to-deliver counts, and each insider's Form 4. A company page pulls every series the site collects for one ticker onto one URL, keyed by the SEC's own ticker list, so the short position, the daily flow, the settlement fails and what insiders are doing can be read together.

Each section has its own history table, a summary sentence built from the rows (last value, change, range with dates) and its own JSON and CSV links. Nothing on the page is written by a model; the sentences change only when the data does. A page exists only for companies with data in at least two series, and every section says when its source last updated.

This page follows MONOLITHIC POWER SYSTEMS, INC. (MPWR), SEC CIK 1280452, listed on Nasdaq, classified by the SEC as semiconductors & related devices. The cross-market tables live on the short interest and insider transactions hubs.

Source and method

Short interest
FINRA consolidated short interestTwice a month, about eight business days after settlement. Latest 2026-08-14.JSON and CSV
Daily short volume
FINRA Reg SHO daily filesEvery trading day, loaded the following morning. Latest 2026-09-11.JSON and CSV
Fails to deliver
SEC fails-to-deliver dataTwice a month, a few weeks after the half month ends. Latest 2026-08-13.JSON and CSV
Planned sales
SEC EDGAR Form 144EDGAR read every 30 minutes; a notice is filed on or before the sell order. Latest 2026-08-24.JSON and CSV
13F holders
SEC EDGAR Form 13F-HRQuarterly, filed within 45 days of quarter end; 30 tracked managers. Latest 2026-06-30.JSON and CSV
Financials
SEC XBRL company factsRefreshed weekly from the SEC's structured data; values are as filed in the 10-Q and 10-K. Latest 2026-06-30.JSON and CSV
Insider trades
SEC EDGAR Form 4EDGAR read every 30 minutes; filings are due two business days after the trade. Latest 2026-08-31.JSON and CSV
Company record
EDGAR filing index for CIK 1280452Ticker, name and exchange from the SEC's company list, refreshed weekly.
Rate limits
30 requests a minute without a key, 120 a minute with a key from a free account.

Data checks. Every dataset is checked against its source once a day. This dataset passed the last run, 13 Sep 05:40 UTC.

How to read it

  • Read the position against the flow: rising short interest with a high daily short share is new shorting; rising short interest with a normal short share is old shorts holding on.
  • Insider buys next to a crowded short are the combination that has historically preceded squeezes; insider sells next to a crowded short are common and mean little.
  • Fails to deliver matter relative to the float, not in absolute shares; a million failed shares in a mega cap is noise.

Analysis of what the data shows, not advice. XOOMAR does not recommend buying, selling or holding anything.

Other companies the SEC classifies as semiconductors & related devices

Datasets

Frequently Asked Questions

How much of MPWR is sold short?
1,839,078 shares were held short at the 2026-08-14 settlement, 2.7 days of average volume. FINRA publishes the next count about eight business days after the 15th and the last business day of the month.
What is MPWR's daily short volume?
On 2026-09-11, 81,541 of the 151,774 MPWR shares reported to FINRA were sold short, 53.7% of the day's reported volume. Short volume is a flow for one day, not a position.
Does MPWR have fails to deliver?
The SEC's latest file shows 41 MPWR shares failed to deliver at settlement 2026-08-13. Fails are reported per settlement date and published twice a month with a lag.
Are MPWR insiders buying or selling?
Insiders at MPWR reported 6 open-market sells worth $367K in the last 90 days and no open-market buys. Sells alone are a weak signal; insiders sell for tax, diversification and estate reasons all the time. Latest filing: Tseng Saria (EVP &amp; General Counsel) on 2026-08-31.
Have MPWR insiders filed to sell?
5 Form 144 notices on file for MPWR worth $20.6M at the prices reported; 5 in the last 90 days worth $20.6M. Latest: DEAN ROBERT W II filed on 2026-08-24 to sell 32 shares ($42K) from 2026-08-24.
What did MPWR report last quarter?
In Q2 2026 (quarter ended 2026-06-30) MONOLITHIC POWER SYSTEMS, INC. reported revenue of $980.6M, up 47.6% from the same quarter a year earlier, and net income of $257.3M (5.22 diluted EPS). In FY 2025 it generated $838.2M of operating cash flow and spent $6.6M on buybacks and $284.8M on dividends.
Which funds hold MPWR?
9 of the 30 tracked managers held MPWR at their latest 13F, $983.4M in total at quarter-end prices. Citadel Advisors is the largest at $305.5M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 5 added shares and 4 cut.

Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.