Monolithic Power Systems, Inc. (MPWR) Ownership
MPWR ownership summary
as of October 18, 2026- Institutions
- 100.5% of shares outstanding
- Insiders
- 3.59% of shares outstanding
- Shares outstanding
- 49.1M
- Float
- 47.4M shares available to trade
- Short interest
- 5.09% 1.9M shares short
- Days to cover
- 2.58 short interest down 2.5% vs prior month
- Institutions 100.47%
- Insiders 3.59%
MPWR top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | BlackRock Inc | 11.37% | 5.6M | $6.77B | −482,542 (−7.9%) | June 30, 2026 |
| 2 | FMR Inc | 10.54% | 5.2M | $6.27B | +776,427 (+17.6%) | June 30, 2026 |
| 3 | Vanguard Capital Management, LLC | 6.36% | 3.1M | $3.79B | +43,307 (+1.4%) | June 30, 2026 |
| 4 | Vanguard Portfolio Management, LLC | 5.10% | 2.5M | $3.03B | −11,634 (−0.5%) | June 30, 2026 |
| 5 | Amvescap Plc. | 4.77% | 2.3M | $2.84B | −172,057 (−6.8%) | June 30, 2026 |
| 6 | State Street Corp | 4.64% | 2.3M | $2.76B | +93,732 (+4.3%) | June 30, 2026 |
| 7 | Geode Capital Management, LLC | 2.43% | 1.2M | $1.45B | −236,785 (−16.5%) | June 30, 2026 |
| 8 | T. Rowe Price Associates, Inc. | 1.99% | 977K | $1.18B | −286,156 (−22.7%) | June 30, 2026 |
| 9 | Franklin Templeton Inc | 1.65% | 812K | $983.2M | −116,697 (−12.6%) | June 30, 2026 |
| 10 | The Goldman Sachs Group Inc | 1.59% | 781K | $945.3M | +212,586 (+37.4%) | June 30, 2026 |
| 11 | NORGES BANK | 1.53% | 751K | $909.8M | +24,694 (+3.4%) | June 30, 2026 |
| 12 | Van Eck Associates Corporation | 1.52% | 746K | $903.6M | +221,666 (+42.3%) | June 30, 2026 |
| 13 | Morgan Stanley - Brokerage Accounts | 1.48% | 728K | $881.4M | +71,518 (+10.9%) | June 30, 2026 |
| 14 | Bank of America Corp | 1.09% | 536K | $649.3M | +154,074 (+40.3%) | June 30, 2026 |
| 15 | Royal Bank of Canada | 0.99% | 487K | $589.9M | +13,844 (+2.9%) | June 30, 2026 |
| 16 | First Trust Advisors L.P. | 0.98% | 483K | $584.6M | −108,572 (−18.4%) | June 30, 2026 |
| 17 | Northern Trust Corp | 0.98% | 479K | $580.6M | −9,628 (−2.0%) | June 30, 2026 |
| 18 | Barclays PLC | 0.96% | 474K | $574.1M | −81,676 (−14.7%) | June 30, 2026 |
| 19 | Rafferty Asset Management, LLC | 0.93% | 459K | $556.1M | +141,805 (+44.7%) | June 30, 2026 |
| 20 | UBS Group AG | 0.91% | 449K | $544.3M | −90,934 (−16.8%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 10 holders added 1.8M shares and 10 cut 1.6M.
MPWR top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Fidelity Select Semiconductors | 3.34% | 1.6M | $1.99B | −201,100 (−10.9%) | August 31, 2026 |
| 2 | Vanguard MStar Total Stk Mkt Idx Invest | 3.02% | 1.5M | $1.80B | −3,012 (−0.2%) | August 31, 2026 |
| 3 | Vanguard 500 Index Investor | 2.63% | 1.3M | $1.56B | −14,616 (−1.1%) | September 30, 2026 |
| 4 | iShares Semiconductor ETF | 2.28% | 1.1M | $1.36B | −11,305 (−1.0%) | September 30, 2026 |
| 5 | Invesco QQQ Trust | 2.09% | 1.0M | $1.24B | −1,672 (−0.2%) | September 30, 2026 |
| 6 | Vanguard MStar Mid Cap Index Instl | 2.03% | 1000K | $1.21B | −9,886 (−1.0%) | September 30, 2026 |
| 7 | VanEck Semiconductor ETF | 1.35% | 661K | $800.6M | +3,766 (+0.6%) | September 30, 2026 |
| 8 | iShares Core S&P 500 ETF | 1.33% | 654K | $792.4M | −1,036 (−0.2%) | September 30, 2026 |
| 9 | Fidelity 500 Index | 1.30% | 638K | $772.2M | +2,450 (+0.4%) | August 31, 2026 |
| 10 | Fidelity Blue Chip Growth | 1.26% | 621K | $752.4M | −7,700 (−1.2%) | August 31, 2026 |
| 11 | State Street® SPDR® S&P 500® ETF | 1.23% | 604K | $731.5M | — | September 30, 2026 |
| 12 | Vanguard MStar Growth Index Investor | 1.15% | 564K | $683.3M | +37,586 (+7.1%) | September 30, 2026 |
| 13 | Direxion Daily Semicondct Bull 3X ETF | 0.79% | 390K | $472.7M | −2,352 (−0.6%) | September 30, 2026 |
| 14 | Vanguard MStar Mid Cap Growth ETF | 0.75% | 367K | $443.8M | +7,966 (+2.2%) | September 30, 2026 |
| 15 | Vanguard Information Technology ETF | 0.73% | 358K | $434.1M | +825 (+0.2%) | September 30, 2026 |
| 16 | State Street®TechSelSectSPDR®ETF | 0.72% | 355K | $429.4M | +216 (+0.1%) | September 30, 2026 |
| 17 | T. Rowe Price Blue Chip Growth | 0.64% | 314K | $380.4M | −13,969 (−4.3%) | September 30, 2026 |
| 18 | MFS Mid Cap Growth A | 0.55% | 271K | $328.2M | −20,429 (−7.0%) | August 31, 2026 |
| 19 | BGF World Technology A2 | 0.55% | 269K | $325.6M | −17,981 (−6.3%) | June 30, 2026 |
| 20 | Vanguard Institutional Index I | 0.53% | 260K | $314.8M | −2,639 (−1.0%) | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
MPWR insider transactions
latest 20| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-04-08 | Saria Tseng | Sell | $1,305.22 | 8,963 | $11.7M |
| 2026-04-06 | Saria Tseng | Sell | $1,167.95 | 7,636 | $8.9M |
| 2026-04-01 | Maurice Sciammas | Sell | $1,116.44 | 30 | $33,493 |
| 2026-04-01 | Saria Tseng | Sell | $1,133.52 | 1,400 | $1.6M |
| 2026-03-30 | Saria Tseng | Sell | $1,010.50 | 25,674 | $25.9M |
| 2026-03-20 | Maurice Sciammas | Sell | $1,095.07 | 30 | $32,852 |
| 2026-03-10 | Ro Khanna | Sell | $1,055.82 | — | — |
| 2026-02-11 | Maurice Sciammas | Sell | $1,179.97 | 200 | $235,994 |
| 2026-02-09 | Victor K Lee | Sell | $1,212.16 | 400 | $484,864 |
| 2026-02-06 | Maurice Sciammas | Sell | $1,171.16 | 22,875 | $26.8M |
| 2026-02-06 | Theodore Blegen | Sell | $1,171.16 | 21,725 | $25.4M |
| 2026-02-06 | Saria Tseng | Sell | $1,171.16 | 22,875 | $26.8M |
| 2026-02-06 | Deming Xiao | Sell | $1,171.16 | 22,875 | $26.8M |
| 2026-02-05 | Ro Khanna | Buy | $1,155.99 | — | — |
| 2026-02-04 | Markwayne Mullin | Buy | $1,136.83 | — | — |
| 2026-02-02 | Theodore Blegen | Sell | $1,129.76 | 3,000 | $3.4M |
| 2026-01-05 | Markwayne Mullin | Buy | $955.03 | — | — |
| 2026-01-02 | Theodore Blegen | Sell | $940.47 | 3,000 | $2.8M |
| 2026-01-02 | Victor K Lee | Sell | $930.86 | 600 | $558,516 |
| 2025-12-24 | Victor K Lee | Sell | $951.72 | 1,000 | $951,720 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
MPWR shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns MPWR
Institutional investors own 100.5% of Monolithic Power's shares and insiders 3.59%. The largest holder is BlackRock Inc with 11.37% of the shares (5.6M), as of June 30, 2026. Among the top 20 institutions, 10 added shares and 10 reduced their stake in the latest filings. Short interest is 5.09% of the float, or 2.58 days of average trading volume. The share count rose 21.9% since 2014.
Related: MPWR analyst forecast, MPWR key metrics, MPWR dividend history. See the MPWR stock overview for the latest quote and news.
MPWR ownership FAQ
Who owns the most Monolithic Power stock?
The largest shareholders of Monolithic Power are BlackRock Inc (11.37%), FMR Inc (10.54%), Vanguard Capital Management, LLC (6.36%), Vanguard Portfolio Management, LLC (5.10%), Amvescap Plc. (4.77%).
What percentage of Monolithic Power is owned by institutions?
Institutions hold 100.5% of Monolithic Power's shares outstanding; insiders hold 3.59%.
Which funds own Monolithic Power?
The largest fund holders of Monolithic Power are Fidelity Select Semiconductors (3.34%), Vanguard MStar Total Stk Mkt Idx Invest (3.02%), Vanguard 500 Index Investor (2.63%), iShares Semiconductor ETF (2.28%), Invesco QQQ Trust (2.09%).
What is Monolithic Power's short interest?
1.9M shares of Monolithic Power were sold short, 5.09% of the float; at the average daily volume it would take 2.58 days to cover.
Are insiders buying or selling Monolithic Power?
Of the latest 20 reported insider transactions in Monolithic Power (since December 24, 2025), 3 were purchases and 17 were sales.
How many shares of Monolithic Power are outstanding?
Monolithic Power has 49.1M shares outstanding, of which 47.4M are in the public float.