Mainstream Capital Management LLC
SEC Form 13F institutional filer · CIK 0002043084
13F-HR · 52 reported holdings · 2026-03-31
Reported long-US-equity value
$0.10B
Top-10 concentration
55.6%
Mainstream Capital Management LLC — $103M AUM allocation strategy
Mainstream Capital Management LLC files SEC Form 13F and reports $103M of long US equity value across 52 reported holdings for 2026-03-31.
Its largest sector bet is Information Technology 17.3%, followed by Financials 16.9% and Communication Services 14.5%.
The top 10 holdings account for 56% 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.
Mainstream Capital Management LLC — latest SEC 13F insights
Reported long-US-equity value (13F AUM)
$103M
total across 52 reported holdings · 2026-03-31 · excludes shorts, cash, non-US
Top-10 concentration
56% of value
higher = narrower conviction; lower = spread / hedging
Biggest adds (shares)
+$GS +50.3K sh · +$2.81M+$SCHW +6.72K sh · +$112K+$WMT +826 sh · +$261K
Biggest trims (shares)
−$AMZN −468 sh · −$811K−$CMG −451 sh · −$154K−$UBER −342 sh · −$137K
Exited to nil (held last quarter, gone now)
$CRM ($1.6M last qtr)$BXP ($838K last qtr)$NKE ($246K last qtr)$CBRE ($238K 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)
- Interactive Media & Services12.4%—
- Investment Banking & Brokerage11.9%—
- Technology Hardware, Storage & Peripherals8.8%—
- Broadline Retail6.3%—
- Semiconductors4.7%—
- Multi-Sector Holdings2.5%—
- Diversified Banks2.5%—
- Consumer Staples Merchandise Retail2.3%—
- Other holdings48.6%—
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
8 of 8 rows · sorted by Value ↓
| Ticker | Holding | Shares | Value | Δ QoQ | Weight |
|---|---|---|---|---|---|
| $GS | Goldman Sachs Group Inc | 178K | $10.5M | +50.3K | 10.2% |
| $AAPL | Apple Inc | 35.6K | $9.02M | -186 | 8.8% |
| $AMZN | Amazon.com Inc | 31.2K | $6.49M | -468 | 6.3% |
| $GOOGL | Alphabet Inc | 20.2K | $5.81M | +75 | 5.6% |
| $NVDA | NVIDIA Corporation | 27.7K | $4.84M | +86 | 4.7% |
| $META | Meta Platforms Inc | 7.57K | $4.33M | -15 | 4.2% |
| $GOOG | Alphabet Inc. Class C Capital Stock | 9.06K | $2.61M | -250 | 2.5% |
| $BRK.B | Berkshire Hathaway Inc.-Class B | 5.4K | $2.59M | +6 | 2.5% |
…and 44 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.
Newsletter signup
Free subscription. Daily trading day morning dispatch. No spam.