Portolan Capital Management, LLC
SEC Form 13F institutional filer · CIK 0001350290
13F-HR · 15 reported holdings · 2026-03-31
Reported long-US-equity value
$0.19B
Top-10 concentration
92.8%
Portolan Capital Management, LLC — $188M AUM allocation strategy
Portolan Capital Management, LLC files SEC Form 13F and reports $188M of long US equity value across 15 reported holdings for 2026-03-31.
Its largest sector bet is Information Technology 70.7%, followed by Health Care 11.5% and Communication Services 10.0%.
The top 10 holdings account for 93% of reported value — a conviction-weighted book concentrated in its best ideas. 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.
Portolan Capital Management, LLC — latest SEC 13F insights
Reported long-US-equity value (13F AUM)
$188M
total across 15 reported holdings · 2026-03-31 · excludes shorts, cash, non-US
Top-10 concentration
93% of value
higher = narrower conviction; lower = spread / hedging
Biggest adds (shares)
+$AMAT +1.32M sh · +$12.3M+$INTC +336K sh · +$1.09M+$EBAY +68K sh · +$6.41M
Biggest trims (shares)
−$AKAM −101K sh · +$2.89M−$T −49.1K sh · −$13.5M−$CIEN −38K sh · −$6.04M
Added from nil (new positions)
None this quarter
Exited to nil (held last quarter, gone now)
$FSLR ($20.6M last qtr)$TECH ($14.6M last qtr)$FCX ($14.6M last qtr)$URI ($8.94M last qtr)$WAT ($8.5M 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)
- Electronic Manufacturing Services26.3%—
- Internet Services & Infrastructure25.8%—
- Biotechnology11.5%—
- Semiconductor Materials & Equipment10.2%—
- Broadline Retail6.1%—
- Communications Equipment6.0%—
- Interactive Media & Services4.0%—
- Interactive Home Entertainment3.4%—
- Other holdings6.7%—
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 |
|---|---|---|---|---|---|
| $AKAM | Akamai Technologies Inc | 423K | $48.6M | -101K | 25.8% |
| $FLEX | Flex Ltd | 443K | $29M | -23.8K | 15.4% |
| $BIIB | Biogen Inc | 118K | $21.7M | +33.5K | 11.5% |
| $JBL | Jabil Inc | 77.2K | $20.5M | +6.53K | 10.9% |
| $AMAT | Applied Materials Inc | 2.39M | $19.2M | +1.32M | 10.2% |
| $EBAY | eBay Inc | 126K | $11.5M | +68K | 6.1% |
| $CIEN | Ciena Corporation | 18.5K | $7.17M | -38K | 3.8% |
| $TTWO | Take-Two Interactive Software Inc | 32.2K | $6.36M | -5.47K | 3.4% |
| $META | Meta Platforms Inc | 10.3K | $5.87M | -57 | 3.1% |
| $T | AT&T Inc | 26.9K | $4.92M | -49.1K | 2.6% |
…and 5 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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