PRIMECAP MANAGEMENT CO/CA/
"13F equity value" = market value of this filer's US-listed long equity positions only. It excludes cash, bonds, non-US and short positions, so it understates a fund's true assets under management — often by a lot.
13F holdings are disclosed ~45 days after quarter-end, and they never reveal when within the quarter a fund actually bought. So any 13F-based summary is structurally late and blurred — this applies to every fund, including this one.
We backtested copying it anyway. Buying this fund's new positions the day each filing went public, over 50 quarters, returned +2.9% per quarter — versus +1.8% per quarter from simply owning every 13F stock. It beat that baseline in only 54.0% of quarters (excess t = 0.38, not statistically significant). Its filings tell you what it bought — not what you should buy.
Quarterly compounding, invested quarters only · entry after the actual SEC deadline plus a 2-day buffer
Top 20 holdings of 324 · 2026 Q2
| Ticker | Value | Weight | QoQ |
|---|---|---|---|
| MU | $22.2B | | TRIM −12% |
| LLY | $11.0B | | HOLD |
| INTC | $10.5B | | HOLD |
| KLAC | $6.2B | | TRIM −16% |
| GOOGL | $5.3B | | HOLD |
| FLEX | $3.8B | | TRIM −8% |
| AZN | $3.4B | | HOLD |
| NVDA | $3.4B | | HOLD |
| BIIB | $3.3B | | ADD +3% |
| AMZN | $2.9B | | HOLD |
| MSFT | $2.7B | | HOLD |
| TSLA | $2.6B | | HOLD |
| FDX | $2.6B | | HOLD |
| TXN | $2.5B | | TRIM −12% |
| LUV | $2.5B | | ADD +4% |
| AMGN | $2.4B | | TRIM −24% |
| SCHW | $2.3B | | ADD +7% |
| UAL | $2.2B | | ADD +5% |
| BSX | $2.2B | | ADD +55% |
| ROST | $1.9B | | HOLD |
QoQ vs previous quarter's share count · NEW = new position · ADD/TRIM = ±2% shares · HOLD = unchanged.
New positions in 2026 Q2
Method & Limitations
Method: a "new position" = held this quarter, absent last quarter (options excluded; stocks with <50 prior holders excluded to filter spin-off artifacts). Entry is the first trading session after the actual SEC filing deadline plus a 2-day buffer. Benchmark = equal-weighted universe of all 13F-held stocks. Limitations: quarterly snapshots can't see intra-quarter trades; survivorship bias — funds that shut down are absent, which flatters the sample. Statistics, not advice.