Atom Investors LP
SEC Form 13F institutional filer · CIK 0001738902
13F-HR · 197 reported holdings · 2026-03-31
Reported long-US-equity value
$0.55B
Top-10 concentration
24.4%
Atom Investors LP — $548M AUM allocation strategy
Atom Investors LP files SEC Form 13F and reports $548M of long US equity value across 197 reported holdings for 2026-03-31.
Its largest sector bet is Utilities 8.3%, followed by Health Care 5.8% and Information Technology 3.9%.
The top 10 holdings account for 24% 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.
Atom Investors LP — latest SEC 13F insights
Reported long-US-equity value (13F AUM)
$548M
total across 197 reported holdings · 2026-03-31 · excludes shorts, cash, non-US
Top-10 concentration
24% of value
higher = narrower conviction; lower = spread / hedging
Biggest adds (shares)
+$PCG +128K sh · +$2.69M+$WBD +89.9K sh · +$2.44M+$MDLZ +85.6K sh · +$4.98M
Biggest trims (shares)
−$NCLH −299K sh · −$6.76M−$BAX −133K sh · −$2.82M−$CSX −104K sh · −$3.02M
Exited to nil (held last quarter, gone now)
$CRM ($14M last qtr)$XLU ($11.4M last qtr)$XLP ($11.2M last qtr)$XLV ($11.1M last qtr)$FFIV ($10.2M last qtr)
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)
- Multi-Utilities4.3%—
- Semiconductors3.9%—
- Life Sciences Tools & Services3.1%—
- Electric Utilities2.8%—
- Data Center REITs2.1%—
- Broadline Retail1.9%—
- Building Products1.5%—
- Pharmaceuticals1.4%—
- Other holdings79.0%—
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
9 of 9 rows · sorted by Value ↓
| Ticker | Holding | Shares | Value | Δ QoQ | Weight |
|---|---|---|---|---|---|
| $TECH | Bio-Techne Corp | 319K | $16.7M | -32.4K | 3.0% |
| $EQIX | Equinix Inc. Common Stock REIT | 12K | $11.7M | — | 2.1% |
| $AVGO | Broadcom Inc | 37.2K | $11.5M | +30K | 2.1% |
| $AMZN | Amazon.com Inc | 49.1K | $10.2M | +34K | 1.9% |
| $NVDA | NVIDIA Corporation | 57.4K | $10M | +25.9K | 1.8% |
| $AEE | Ameren Corporation | 80.8K | $8.89M | +56.1K | 1.6% |
| $LNT | Alliant Energy Corporation | 118K | $8.5M | +33.4K | 1.6% |
| $BLDR | Builders FirstSource Inc | 102K | $8.4M | +50.9K | 1.5% |
| $BMY | Bristol-Myers Squibb Company | 125K | $7.55M | — | 1.4% |
…and 188 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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