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Monolithic Power Systems, Inc.

MPWR
Exchange
Nasdaq
Industry
Semiconductors & Related Devices
SEC CIK
0001280452

In the last 90 days, Monolithic Power Systems, Inc. insiders filed 0 open-market purchases and 5 sales; 1,258 institutions reported holding it in 13F filings for Q2 2026, worth $65.6B in total; superinvestors D1 Capital Partners and Maverick Capital hold it.

Four kinds of short-selling data, each measuring something different:

  • Short interest: shares sold short and not yet bought back, as of a settlement date. FINRA publishes it twice a month, about eight business days after the settlement date.
  • Daily short volume: shares sold short each day in off-exchange trades reported to FINRA. It counts trades, not open positions, and is published the next day.
  • Fails-to-deliver: shares not delivered by the settlement date. The SEC publishes them twice a month, about two weeks late.
  • ATS (dark pool) volume: weekly volume on alternative trading systems and other off-exchange venues. FINRA publishes it two to four weeks after the week.

More in the glossary.

Short interest

Shares sold short and not yet bought back, from FINRA, on every settlement date in the last two years.

Short interest
1.59M
Shares, settlement Oct 30, 2026
Change
−13.1K
−0.8% vs. Oct 15, 2026
Days to cover
1.74
Short interest ÷ average daily volume
Average daily volume
913.4K
Shares, as reported by FINRA
Short interest by settlement date
Oct 31, 2024: 1,494,353 sharesNov 15, 2024: 2,515,277 sharesNov 29, 2024: 2,092,966 sharesDec 13, 2024: 2,324,251 sharesDec 31, 2024: 2,852,221 sharesJan 15, 2025: 2,594,479 sharesJan 31, 2025: 2,744,323 sharesFeb 14, 2025: 2,719,973 sharesFeb 28, 2025: 2,602,443 sharesMar 14, 2025: 2,299,084 sharesMar 31, 2025: 2,452,999 sharesApr 15, 2025: 2,630,420 sharesApr 30, 2025: 2,021,634 sharesMay 15, 2025: 2,445,033 sharesMay 30, 2025: 1,955,312 sharesJun 13, 2025: 1,893,692 sharesJun 30, 2025: 2,300,158 sharesJul 15, 2025: 2,434,201 sharesJul 31, 2025: 2,401,819 sharesAug 15, 2025: 2,319,594 sharesAug 29, 2025: 1,920,230 sharesSep 15, 2025: 1,619,039 sharesSep 30, 2025: 2,051,204 sharesOct 15, 2025: 1,881,672 sharesOct 31, 2025: 1,667,795 sharesNov 14, 2025: 1,796,489 sharesNov 28, 2025: 1,850,349 sharesDec 15, 2025: 1,729,984 sharesDec 31, 2025: 2,855,358 sharesJan 15, 2026: 2,313,245 sharesJan 30, 2026: 2,304,227 sharesFeb 13, 2026: 2,099,811 sharesFeb 27, 2026: 2,054,245 sharesMar 13, 2026: 1,987,899 sharesMar 31, 2026: 1,985,296 sharesApr 15, 2026: 1,825,570 sharesApr 30, 2026: 1,720,835 sharesMay 15, 2026: 1,975,414 sharesMay 29, 2026: 2,319,453 sharesJun 15, 2026: 2,348,322 sharesJun 30, 2026: 2,214,362 sharesJul 15, 2026: 2,456,955 sharesJul 31, 2026: 2,122,311 sharesAug 14, 2026: 1,839,078 sharesAug 31, 2026: 1,998,007 sharesSep 15, 2026: 1,906,839 sharesSep 30, 2026: 1,858,921 sharesOct 15, 2026: 1,602,872 sharesOct 30, 2026: 1,589,806 shares
Short interest in MPWR by settlement date
Settlement dateShort interestChangeChange %Avg. daily volumeDays to cover
Oct 30, 20261.59M−13.1K−0.8%913.4K1.74
Oct 15, 20261.60M−256.0K−13.8%688.3K2.33
Sep 30, 20261.86M−47.9K−2.5%799.0K2.33
Sep 15, 20261.91M−91.2K−4.6%606.9K3.14
Aug 31, 20262.00M+158.9K+8.6%603.2K3.31
Aug 14, 20261.84M−283.2K−13.4%672.6K2.73
Jul 31, 20262.12M−334.6K−13.6%997.5K2.13
Jul 15, 20262.46M+242.6K+11.0%919.3K2.67
Jun 30, 20262.21M−134.0K−5.7%1.48M1.50
Jun 15, 20262.35M+28.9K+1.2%772.0K3.04
May 29, 20262.32M+344.0K+17.4%709.7K3.27
May 15, 20261.98M+254.6K+14.8%643.8K3.07
Apr 30, 20261.72M−104.7K−5.7%622.8K2.76
Apr 15, 20261.83M−159.7K−8.1%539.1K3.39
Mar 31, 20261.99M−2.60K−0.1%536.1K3.70
Mar 13, 20261.99M−66.3K−3.2%564.4K3.52
Feb 27, 20262.05M−45.6K−2.2%452.0K4.54
Feb 13, 20262.10M−204.4K−8.9%844.1K2.49
Jan 30, 20262.30M−9.02K−0.4%615.6K3.74
Jan 15, 20262.31M−542.1K−19.0%522.1K4.43
Dec 31, 20252.86M+1.13M+65.1%917.7K3.11
Dec 15, 20251.73M−120.4K−6.5%523.4K3.31
Nov 28, 20251.85M+53.9K+3.0%732.9K2.52
Nov 14, 20251.80M+128.7K+7.7%663.6K2.71
Oct 31, 20251.67M−213.9K−11.4%684.8K2.44
Oct 15, 20251.88M−169.5K−8.3%567.8K3.31
Sep 30, 20252.05M+432.2K+26.7%502.1K4.09
Sep 15, 20251.62M−301.2K−15.7%464.0K3.49
Aug 29, 20251.92M−399.4K−17.2%483.4K3.97
Aug 15, 20252.32M−82.2K−3.4%746.5K3.11
Jul 31, 20252.40M−32.4K−1.3%548.0K4.38
Jul 15, 20252.43M+134.0K+5.8%496.7K4.90
Jun 30, 20252.30M+406.5K+21.5%551.2K4.17
Jun 13, 20251.89M−61.6K−3.2%564.9K3.35
May 30, 20251.96M−489.7K−20.0%539.0K3.63
May 15, 20252.45M+423.4K+20.9%870.0K2.81
Apr 30, 20252.02M−608.8K−23.1%824.1K2.45
Apr 15, 20252.63M+177.4K+7.2%1.52M1.73
Mar 31, 20252.45M+153.9K+6.7%960.4K2.55
Mar 14, 20252.30M−303.4K−11.7%852.4K2.70
Feb 28, 20252.60M−117.5K−4.3%871.1K2.99
Feb 14, 20252.72M−24.4K−0.9%997.2K2.73
Jan 31, 20252.74M+149.8K+5.8%996.5K2.75
Jan 15, 20252.59M−257.7K−9.0%649.3K4.00
Dec 31, 20242.85M+528.0K+22.7%796.0K3.58
Dec 13, 20242.32M+231.3K+11.1%811.8K2.86
Nov 29, 20242.09M−422.3K−16.8%1.13M1.85
Nov 15, 20242.52M+1.02M+68.3%1.54M1.63
Oct 31, 20241.49M+202.6K+15.7%752.6K1.99

Fails-to-deliver

Shares that weren't delivered by the settlement date, from the SEC, for the last 30 dates with fails. The price is the previous day's closing price published by the SEC.

Fails-to-deliver in MPWR by settlement date
Settlement dateSharesPriceValue
Oct 13, 20262,314$1,319.23$3.05M
Oct 2, 202624$1,360.97$32.7K
Sep 21, 202640$1,217.80$48.7K
Sep 17, 202640$1,147.61$45.9K
Aug 13, 202641$1,425.01$58.4K
Aug 3, 20261$1,426.03$1.43K
Jul 17, 202638$1,305.65$49.6K
Jul 10, 2026665$1,374.13$913.8K
Jul 2, 2026224$1,331.73$298.3K
Jul 1, 20267,880$1,382.36$10.9M
Jun 30, 20267,906$1,312.77$10.4M
Jun 29, 2026151,827$1,313.32$199.4M
Jun 25, 202631$1,434.95$44.5K
Jun 22, 20268,983$1,563.70$14.0M
Jun 18, 2026214$1,448.21$309.9K
Jun 16, 202617,033$1,652.29$28.1M
Jun 15, 2026155$1,577.32$244.5K
Jun 12, 20263,945$1,589.55$6.27M
Jun 11, 202611,381$1,473.04$16.8M
Jun 9, 2026725$1,559.18$1.13M
May 29, 2026573$1,633.17$935.8K
May 19, 2026150$1,486.33$222.9K
May 18, 2026500$1,550.02$775.0K
May 14, 20263$1,650.35$4.95K
May 7, 2026170$1,652.35$280.9K
May 1, 20261,894$1,614.41$3.06M
Apr 24, 2026421$1,592.17$670.3K
Apr 20, 2026282$1,468.35$414.1K
Apr 16, 20261,210$1,353.00$1.64M
Apr 15, 20261$1,363.42$1.36K

Daily short volume

Off-exchange short-sale volume, not short interest: shares sold short each day in trades reported to FINRA, for the last 30 trading days.

The short volume ratio isn't a sentiment gauge: market makers sell short to fill buy orders and to hedge, so short sales are usually about half of off-exchange volume.

Off-exchange short volume in MPWR by trade date
Trade dateShort volumeShort exemptOff-exchange volumeShort volume ratio
Nov 10, 2026123,03048324,29237.9%
Nov 9, 2026242,317130454,37653.3%
Nov 6, 2026121,2143,406395,52630.6%
Nov 5, 2026224,2468,102801,85628.0%
Nov 4, 202697,08878399,57824.3%
Nov 3, 2026201,416263471,70142.7%
Nov 2, 2026150,163148425,03935.3%
Oct 30, 2026356,0106654,17854.4%
Oct 29, 2026127,51252253,03250.4%
Oct 28, 202662,35116193,57032.2%
Oct 27, 202677,7950221,18835.2%
Oct 26, 202664,98410248,97126.1%
Oct 23, 202685,8854,110220,00939.0%
Oct 22, 2026185,398230411,44845.1%
Oct 21, 202681,89922213,64738.3%
Oct 20, 202679,28999184,51543.0%
Oct 19, 2026122,5438345,26935.5%
Oct 16, 2026103,01581222,74946.2%
Oct 15, 2026127,2151293,04343.4%
Oct 14, 2026130,6905308,68542.3%
Oct 13, 202682,34950209,16039.4%
Oct 12, 202664,80273235,14227.6%
Oct 9, 202658,96011161,25136.6%
Oct 8, 2026110,60517222,30249.8%
Oct 7, 202683,1151121,58668.4%
Oct 6, 202676,787232124,52761.7%
Oct 5, 2026172,0491271,34063.4%
Oct 2, 2026155,02561277,94155.8%
Oct 1, 202677,7288142,83154.4%
Sep 30, 202659,68189116,93951.0%

ATS (dark pool) volume

Weekly volume on alternative trading systems (ATS) and other off-exchange (OTC) venues, from FINRA, for the last 12 weeks. ATS share is ATS volume ÷ (ATS + OTC volume), not a share of all trading.

Weekly ATS and OTC volume in MPWR
Week ofTierATS sharesATS tradesOther OTC sharesOther OTC tradesATS share
Oct 19, 2026T11,133,65078,122327,15627,26777.6%
Oct 12, 2026T11,013,24290,087583,17130,51563.5%
Oct 5, 2026T1730,67866,837360,75024,80266.9%
Sep 28, 2026T1646,46555,956404,66923,84261.5%
Sep 21, 2026T1945,31469,452826,77029,91953.3%
Sep 14, 2026T1811,23467,172824,79124,96549.6%
Sep 7, 2026T1590,99851,804254,68917,53369.9%
Aug 31, 2026T1697,21661,118372,10923,10265.2%
Aug 24, 2026T1620,55857,195504,15722,98855.2%
Aug 17, 2026T1748,82564,125497,92424,69460.1%
Aug 10, 2026T1491,19347,098398,00623,56755.2%
Aug 3, 2026T11,152,89286,639577,47032,93866.6%