WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC
Position in POWI — Power Integrations Inc
CIK 1644956
CHICAGO, IL
Position in POWI
as of Jun 30, 2026
· filed Aug 12, 2026
Position Value
$199,516,906
+$77,626,244 QoQ
Shares Held
2,382,007
+0.1% QoQ
Ownership
4.26%
of shares outstanding
% of Portfolio
0.61%
of 13F equity value
Holder Rank
#6
of 372 holders
Holding Since
Sep 2021
17 quarters on record
Voting authority
Sole 92%
Shared 0%
None 8%
Common Shares in POWI Over Time
Shares Held
Position Value (USD)
Position in Semiconductors
Technology · as of Jun 30, 2026WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC holds $6,354,141,039 across 17 Semiconductors names. POWI ranks #5 (3.1% of the industry book) .
| # | Ticker | Company | Shares | Value (USD) | Open |
|---|---|---|---|---|---|
| 1 | TSM |
Taiwan Semiconductor Manufacturing Co Ltd
|
4,936,408 | $2,357,480,368 | |
| 2 | NVDA |
Nvidia Corp
|
8,599,021 | $1,720,578,111 | |
| 3 | AVGO |
Broadcom Inc.
|
2,056,135 | $776,704,996 | |
| 4 | AMD |
Advanced Micro Devices Inc
|
763,517 | $443,534,660 | |
| 5 | POWI |
Power Integrations Inc
This page
|
2,382,007 | $199,516,906 | |
| 6 | DIOD |
Diodes Inc /Del/
|
1,682,686 | $184,153,155 | |
| 7 | LSCC |
Lattice Semiconductor Corp
|
1,160,417 | $177,497,384 | |
| 8 | SYNA |
SYNAPTICS Inc
|
1,239,622 | $153,998,241 |
All Filings in POWI
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17 filing rows on record
| Report Date | Value (USD) | Shares | Type | Discretion | Filed | |
|---|---|---|---|---|---|---|
| 2026-06-30 | $199,516,906 | 2,382,007 | Shares | Sole | 2026-08-12 | |
| 2026-03-31 | $121,890,662 | 2,380,677 | Shares | Sole | 2026-05-08 | |
| 2025-03-31 | $353,752 | 7,005 | Shares | Sole | 2025-05-09 | |
| 2024-12-31 | $628,599 | 10,188 | Shares | Sole | 2025-02-10 | |
| 2024-09-30 | $658,384 | 10,268 | Shares | Sole | 2024-11-08 | |
| 2024-06-30 | $574,856 | 8,190 | Shares | Sole | 2024-08-08 | |
| 2024-03-31 | $21,177,440 | 295,981 | Shares | Sole | 2024-05-08 | |
| 2023-12-31 | $23,498,650 | 286,185 | Shares | Sole | 2024-02-09 | |
| 2023-09-30 | $19,113,899 | 250,477 | Shares | Sole | 2023-11-09 | |
| 2023-06-30 | $18,978,873 | 200,474 | Shares | Sole | 2023-08-11 | |
| 2023-03-31 | $18,077,157 | 213,577 | Shares | Sole | 2023-05-12 | |
| 2022-12-31 | $10,985,711 | 153,175 | Shares | Sole | 2023-02-09 | |
| 2022-09-30 | $9,633,592 | 149,776 | Shares | Sole | 2022-11-09 | |
| 2022-06-30 | $31,185,182 | 415,747 | Shares | Sole | 2022-08-10 | |
| 2022-03-31 | $42,718,158 | 460,921 | Shares | Sole | 2022-05-11 | |
| 2021-12-31 | $35,409,946 | 381,203 | Shares | Sole | 2022-02-14 | |
| 2021-09-30 | $16,849,978 | 170,219 | Shares | Sole | 2021-11-10 | |
| No filing history on record for this holder in this stock. | ||||||