Monolithic Power Systems, Inc.
US ˙ NasdaqGS ˙ US6098391054

SecurityMPWR / Monolithic Power Systems, Inc.
InstitutionBlair William & Co/il
Latest Disclosed Ownership297,365 shares
Ownership 0.84%
Blair William & Co/il ownership in MPWR / Monolithic Power Systems, Inc.

2013-02-04 - Blair William & Co/il has filed an SC 13G/A form with the Securities and Exchange Commission (SEC) disclosing ownership of 297,365 shares of Monolithic Power Systems, Inc. (US:MPWR). This represents 0.84 percent ownership of the company.

Blair William & Co/il has a history of taking positions in derivatives of the underlying security (MPWR) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

Institutional Ownership: 13D/G Filings

This table shows a history of the 13D/G filings made by the investor and/or investor group. Note that the share values in this table are not directly comparable to any numbers shown in the 13F table (if any).

File
Date
Effective
Date
Form Prev
Shares
Latest
Shares
ΔShares
(Percent)
Ownership
(Percent)
ΔOwnership
(Percent)
2013-02-04 2013-02-04 13G/A 297,365 0.84
2012-08-07 2012-08-07 13G/A 1,973,658 5.66
2012-01-30 2012-01-30 13G/A 3,745,832 11.12

Important Note: One of the primary uses of the 13D/G filings is to evaluate the ability of a firm to control a company (ie, the "beneficial ownership"). To that end, firms are required to report not just direct holdings in companies, but indirect holdings that they control. For investment firms, these indirect holdings can include shares in funds they manage, advisory accounts, and in the case of activist campaigns, pledged votes. Therefore, share counts listed in 13D/G filings can differ significantly than share counts listed in 13F filings.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

MPWR / Monolithic Power Systems, Inc. Historical Put/Call Ratio
Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date
Effective
Date
Form Security Class ID Avg Price
Paid (Est)
Reported
Shares
ΔShares ΔShares
(%)
Reported
Value
(x1000)
ΔValue
(%)
Alloc
(%)
ΔAlloc ΔAlloc (%) Cost Basis
(x1000)
Unrealized
Gain/Loss
(x1000)
2026-05-08 2026-03-31 13F MONOLITHIC PWR SYS COM 609839105 30,557 16,910 123.91 33,410 170.12 0.0957
2026-02-17 2025-12-31 13F MONOLITHIC PWR SYS COM 609839105 13,647 3,465 34.03 12,369 31.94 0.0332
2025-11-12 2025-09-30 13F MONOLITHIC PWR SYS COM 609839105 10,182 1,195 13.30 9,374 42.64 0.0250
2025-07-24 2025-06-30 13F MONOLITHIC PWR SYS COM 609839105 8,987 -521 -5.48 6,573 19.19 0.0183
2025-05-09 2025-03-31 13F MONOLITHIC PWR SYS COM 609839105 9,508 -1,850 -16.29 5,514 -17.95 0.0166
2025-02-12 2024-12-31 13F MONOLITHIC PWR SYS COM 609839105 11,358 1,759 18.32 6,721 -24.27 0.0195
2024-11-12 2024-09-30 13F MONOLITHIC PWR SYS COM 609839105 9,599 1 0.01 8,874 12.53 0.0261
2024-08-12 2024-06-30 13F MONOLITHIC PWR SYS COM 609839105 9,598 113 1.19 7,887 22.74 0.0243
2024-05-09 2024-03-31 13F MONOLITHIC PWR SYS COM 609839105 9,485 -1,990 -17.34 6,425 -11.23 0.0202
2024-02-12 2023-12-31 13F MONOLITHIC PWR SYS COM 609839105 11,475 -33 -0.29 7,238 36.16 0.0247
2023-11-09 2023-09-30 13F MONOLITHIC PWR SYS COM 609839105 11,508 -10,369 -47.40 5,317 -55.02 0.0204
2023-08-11 2023-06-30 13F MONOLITHIC PWR SYS COM 609839105 21,877 -1,485 -6.36 11,819 1.07 0.0433
2023-05-12 2023-03-31 13F MONOLITHIC PWR SYS COM 609839105 23,362 67 0.29 11,694 41.96 0.0467
2023-02-10 2022-12-31 13F MONOLITHIC PWR SYS COM 609839105 23,295 3,396 17.07 8,237 13.91 0.0358
2022-11-09 2022-09-30 13F MONOLITHIC PWR SYS COM 609839105 19,899 6,616 49.81 7,231 41.76 0.0332
2022-08-10 2022-06-30 13F MONOLITHIC PWR SYS COM 609839105 13,283 2,948 28.52 5,101 1.63 0.0226
2022-05-13 2022-03-31 13F MONOLITHIC PWR SYS COM 609839105 10,335 883 9.34 5,019 7.63 0.0176
2022-02-14 2021-12-31 13F MONOLITHIC PWR SYS COM 609839105 9,452 2,469 35.36 4,663 37.75 0.0146
2021-11-12 2021-09-30 13F MONOLITHIC PWR SYS COM 609839105 6,983 -3,273 -31.91 3,385 -11.62 0.0115
2021-08-12 2021-06-30 13F MONOLITHIC PWR SYS COM 609839105 10,256 -316 -2.99 3,830 2.57 0.0133
2021-05-13 2021-03-31 13F MONOLITHIC PWR SYS COM 609839105 10,572 97 0.93 3,734 -2.66 0.0141
2021-02-09 2020-12-31 13F MONOLITHIC PWR SYS COM 609839105 10,475 237 2.31 3,836 33.99 0.0141
2020-11-06 2020-09-30 13F MONOLITHIC PWR SYS COM 609839105 10,238 70 0.69 2,863 18.80 0.0121
2020-08-12 2020-06-30 13F MONOLITHIC PWR SYS COM 609839105 10,168 -204 -1.97 2,410 38.74 0.0115
2020-05-11 2020-03-31 13F MONOLITHIC PWR SYS COM 609839105 10,372 1,807 21.10 1,737 13.90 0.0109
2020-02-13 2019-12-31 13F MONOLITHIC PWR SYS COM 609839105 8,565 151 1.79 1,525 16.50 0.0078
2019-11-12 2019-09-30 13F MONOLITHIC PWR SYS COM 609839105 8,414 5,901 234.82 1,309 283.87 0.0075
2019-08-13 2019-06-30 13F MONOLITHIC PWR SYS COM 609839105 2,513 -1,329 -34.59 341 -34.55 0.0019
2019-05-14 2019-03-31 13F MONOLITHIC PWR SYS COM 609839105 3,842 962 33.40 521 55.52 0.0032
2019-02-14 2018-12-31 13F MONOLITHIC PWR SYS COM 609839105 2,880 -558 -16.23 335 -22.45 0.0024
2018-11-13 2018-09-30 13F MONOLITHIC PWR SYS COM 609839105 3,438 -1,846 -34.94 432 -38.81 0.0026
2018-08-13 2018-06-30 13F MONOLITHIC PWR SYS COM 609839105 5,284 -1,350 -20.35 706 -8.07 0.0048
2018-05-15 2018-03-31 13F MONOLITHIC PWR SYS COM 609839105 6,634 -100 -1.49 768 1.45 0.0054
2018-02-14 2017-12-31 13F MONOLITHIC PWR SYS COM 609839105 6,734 -50 -0.74 757 4.70 0.0051
2017-11-13 2017-09-30 13F MONOLITHIC POWER SYSTEMS COM 609839105 6,784 0 0.00 723 10.55 0.0054
2017-08-04 2017-06-30 13F MONOLITHIC POWER SYSTEMS COM 609839105 6,784 166 2.51 654 11.60 0.0049
2017-05-10 2017-03-31 13F MONOLITHIC POWER SYSTEMS COM 609839105 6,618 -2,384 -26.48 586 -20.60 0.0047
2017-02-14 2016-12-31 13F MONOLITHIC POWER SYSTEMS COM 609839105 9,002 -2,213 -19.73 738 -18.27 0.0066
2016-11-14 2016-09-30 13F MONOLITHIC POWER SYSTEMS COM 609839105 11,215 1,434 14.66 903 35.18 0.0080
2016-08-08 2016-06-30 13F MONOLITHIC POWER SYSTEMS COM 609839105 9,781 0 0.00 668 7.40 0.0062
2016-05-16 2016-03-31 13F MONOLITHIC POWER SYSTEMS COM 609839105 9,781 -10,665 -52.16 622 -52.26 0.0059
2016-02-16 2015-12-31 13F MONOLITHIC POWER SYSTEMS COM 609839105 20,446 -6,650 -24.54 1,303 -6.06 0.0122
2015-11-12 2015-09-30 13F MONOLITHIC POWER SYSTEMS COM 609839105 27,096 -58,233 -68.25 1,387 -83.27 0.0120
2015-08-03 2015-06-30 13F BLUE DART EXPRESS COM 006098601 85,329 -13,238 -13.43 8,292 -27.88 0.0124
2015-05-11 2015-03-31 13F BLUE DART EXPRESS COM 006098601 98,567 98,567 11,497 0.0177
2015-02-05 2014-12-31 13F BLUE DART EXPRESS COM 006098601 0 -18,796 -100.00 0 -100.00
2014-11-04 2014-09-30 13F MONOLITHIC POWER SYSTEMS COM 609839105 18,796 -25,114 -57.19 827 -55.51 0.0014
2014-11-04 2014-09-30 13F BLUE DART EXPRESS COM 006098601 111,128 -17,115 9,514 0.0163
2014-08-01 2014-06-30 13F MONOLITHIC POWER SYSTEMS COM 609839105 43,910 -344,540 -88.70 1,859 -87.66 0.0030
2014-08-01 2014-06-30 13F BLUE DART EXPRESS COM 006098601 128,243 11,103 8,962 0.0146
2014-05-06 2014-03-31 13F MONOLITHIC POWER SYSTEMS COM 609839105 388,450 359,086 1,222.88 15,060 837.73 0.0249
2014-05-06 2014-03-31 13F BLUE DART EXPRESS COM 006098601 117,140 87,776 7,298 0.0121
2014-02-11 2013-12-31 13F BLUE DART EXPRESS COM 006098601 29,364 -304,529 -91.21 1,606 -84.11 0.0027
2013-11-12 2013-09-30 13F MONOLITHIC POWER SYSTEMS COM 609839105 333,893 -401,475 -54.60 10,110 -42.98 0.0180
2013-08-07 2013-06-30 13F MONOLITHIC POWER SYSTEMS COM 609839105 735,368 735,368 17,730 0.0351
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2015-02-05 2014-12-31 13F MONOLITHIC POWER SYS OPTION Call 0 -100.00 0 -100.00 n/a n/a n/a
2014-11-04 2014-09-30 13F MONOLITHIC POWER SYS OPTION Call 2,000 88 n/a n/a n/a
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.