PRIMECAP MANAGEMENT CO/CA/
SEC Form 13F institutional filer · CIK 0000763212
13F-HR · 162 reported holdings · 2026-03-31
Asset management firm, known for long-term growth investing.
Reported long-US-equity value
$99.40B
Top-10 concentration
41.9%
PRIMECAP MANAGEMENT CO/CA/ — $99.4B AUM allocation strategy
PRIMECAP MANAGEMENT CO/CA/ files SEC Form 13F and reports $99.4B of long US equity value across 162 reported holdings for 2026-03-31.
Its largest sector bet is Information Technology 23.7%, followed by Health Care 16.5% and Consumer Discretionary 8.4%.
The top 10 holdings account for 42% of reported value — a broadly spread portfolio. The sector and industry splits below are of the same reported value. Track quarter-over-quarter adds, trims, new positions and exits below — sourced from SEC 13F filings, public domain.
PRIMECAP MANAGEMENT CO/CA/ — latest SEC 13F insights
Reported long-US-equity value (13F AUM)
$99.4B
total across 162 reported holdings · 2026-03-31 · excludes shorts, cash, non-US
Top-10 concentration
42% of value
higher = narrower conviction; lower = spread / hedging
Biggest adds (shares)
+$HPQ +3.81M sh · +$19.1M+$PYPL +1.86M sh · −$23.4M+$BSX +1.43M sh · −$924M
Biggest trims (shares)
−$MU −2.92M sh · +$313M−$HPE −1.98M sh · −$51.3M−$QCOM −1.63M sh · −$309M
Exited to nil (held last quarter, gone now)
None this quarter
Sector allocation (share of reported value)
each slice is a share of the reported long-US-equity value — smaller sectors and the rest of the book roll into “Other holdings”
Qtr shift = share-point change vs the prior quarter's filing — first period tracked for this filer; the column fills in with the next quarterly refresh.
Industry allocation (share of reported value)
- Semiconductors15.7%—
- Pharmaceuticals8.5%—
- Interactive Media & Services6.0%—
- Biotechnology5.8%—
- Semiconductor Materials & Equipment3.6%—
- Apparel Retail3.6%—
- Air Freight & Logistics3.0%—
- Systems Software2.7%—
- Other holdings51.1%—
the finer GICS cut of the same book — same denominator — smaller industries roll into “Other holdings”
Qtr shift = share-point change vs the prior quarter's filing — first period tracked for this filer; the column fills in with the next quarterly refresh.
Top S&P 500 holdings
10 of 10 rows · sorted by Value ↓
| Ticker | Holding | Shares | Value | Δ QoQ | Weight |
|---|---|---|---|---|---|
| $LLY | Eli Lilly and Company | 9.22M | $8.48B | -42.4K | 8.5% |
| $MU | Micron Technology Inc | 21.9M | $7.39B | -2.92M | 7.4% |
| $GOOG | Alphabet Inc. Class C Capital Stock | 15M | $4.31B | -141K | 4.3% |
| $KLAC | KLA Corporation | 2.44M | $3.59B | -438K | 3.6% |
| $INTC | Intel Corporation | 79M | $3.37B | +182K | 3.4% |
| $AMGN | Amgen Inc | 8.87M | $3.12B | -30.9K | 3.1% |
| $NVDA | NVIDIA Corporation | 17.2M | $3B | -39.3K | 3.0% |
| $FDX | FedEx Corporation | 8.3M | $2.96B | -210K | 3.0% |
| $BIIB | Biogen Inc | 14.8M | $2.71B | -390 | 2.7% |
| $MSFT | Microsoft Corporation | 7.26M | $2.69B | -23K | 2.7% |
…and 152 more holdings in the full 13F filing (top positions only shown).
SEC Form 13F data sets · public domain · 45-day filing lag · >$100M AUM managers · as reported
← All 13F filers·← QuantOrb.pro
How to read Δ QoQ — the five insight categories, and the caveats
The categories. Analysts, quants and retail traders look past total portfolio value to isolate actionable signals. Five categories matter.
Conviction & concentration shifts
New positions vs complete exits — a brand-new stock signals high conviction; a full liquidation suggests a broken thesis or tax-loss harvesting. Aggressive sizing — look at share count, not dollars: a 20% share increase during a drawdown is strong dip-buying. Concentration — a narrowing top-5/10 means conviction; spreading capital across more names means hedging.
Sector & macro allocation rotations
Aggregating Δ QoQ moves across sectors shows where smart money is leaning in or sneaking out — rotating out of growth into defensives or energy, for example. The fund's total long equity exposure quarter-over-quarter is a proxy for overall institutional risk appetite.
Crowding & smart-money consensus
When several managers initiate or expand the same stock in the same quarter, that is institutional consensus. Contrarian reads: top pickers buying hard into a beaten-down name the market is selling.
Derivative & option overlays
Reported call/put changes indicate whether managers are adding downside hedges or leveraging upside exposure. Note: a long increase may be half of a market-neutral pair trade.
Who reads this
| Retail "cloners" | High-conviction ideas to replicate ~45 days after quarter-end. |
| Corporate IR | Which funds bought or dumped the stock, before the next call. |
| Quant / algo traders | Cross-sectional factor inputs: flow, momentum, ownership. |
Four caveats before you trade on it
- 45-day lag — holdings are quarter-end; positions may already be closed.
- Long-only — 13Fs miss shorts, pair trades and cash.
- No non-US / fixed income — the picture is US equities plus options.
- Corporate actions — splits and spinoffs distort raw share deltas.
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