Stock Whale Activity
Track large stock trades across S&P 500 companies. Monitor buy vs sell flow, dark pool vs lit exchange activity, and sector-level sentiment to understand where meaningful capital is moving. This dashboard reflects a rolling lookback of the last 5 trading days.
Open Source & Transparent
All data is open source and verifiable on GitHub. We believe in transparency and welcome contributions to improve our tools.
Minimum Trade
$1M+
Universe
S&P 500
Includes
Dark Pools
Lookback
Last 5 Trading Days
Understanding stock whale activity
Large equity prints can signal institutional activity, but they require context. Use this section to interpret tiers, dark pool flow, and direction estimates responsibly.
General overview: what this dashboard is measuring
This dashboard aggregates large stock prints across S&P 500 names and summarizes flow by ticker, sector, and venue. A single large trade can reflect many motives—directional bets, hedges, rebalances, or execution of existing orders.
The most useful signal is often persistence: repeated activity in the same name, a consistent buy/sell skew, and supportive context from price/volume and catalysts.
Use the lookback window as a stabilizer. It helps you avoid overreacting to isolated prints and focus on sustained flow.
Detailed breakdown: key concepts to read the flow
These cards explain the highest-signal parts of the dashboard: tiers, venue, direction estimates, and sentiment summaries.
Whale flow checklist
Signal strength ↑ when Size tier is high AND net flow persists AND venue/direction make sense
A clean read usually requires agreement: large notional prints + consistent net flow + plausible execution venue. Treat direction estimates as probabilities, not facts.
$1M+
Minimum notional
5D
Rolling lookback
Dark/Lit
Venue split
Tip: pair this page with S&P 500 Index Directory for fundamentals context.
What is stock whale flow?
Unusually large equity prints
- Definition: large prints that can reflect institutional participation.
- Why it matters: can help you identify names with concentrated capital activity.
- Best practice: focus on repeated flow, not one-off trades.
Trade size tiers
Notable → Mega whale
- Use it for: prioritization—higher tiers imply larger notional exposure.
- Trap: tier alone doesn’t imply direction or profitability.
- Workflow: confirm tier + direction estimate + price behavior.
Dark pools vs lit exchanges
Execution venue context
- Dark pools: off-exchange venues often used to reduce market impact.
- Lit exchanges: more transparent prints on public venues.
- Use it for: understanding how institutions may be executing size.
Bullish vs bearish sentiment
Buy/sell ratio and net flow
- Look for: persistent positive net flow and stronger buy/sell ratios.
- Beware: prints can be hedges or index flows—context is required.
- Use with: price/volume and catalyst awareness for validation.
Direction estimation (Lee-Ready)
Bid/ask inference
- How it works: infers buy vs sell likelihood from trade price vs bid/ask.
- Limitations: can be noisy in fast markets and around spreads.
- Best practice: treat as a confidence-weighted estimate, not a guarantee.
Frequently asked questions
What is a stock whale trade? ▼
A stock whale trade is a very large equity print, typically defined by high notional value and/or share size. These trades are often associated with institutional activity and can provide useful context for where meaningful capital is flowing.
How is buy vs sell direction estimated? ▼
Direction is estimated using trade price relative to bid/ask (a common approach known as the Lee-Ready algorithm). It provides an informed estimate of whether prints are more likely buyer-initiated or seller-initiated, but it is not perfect.
What is dark pool activity and why does it matter? ▼
Dark pools are off-exchange venues where trades can be executed with reduced market impact and lower visibility. Monitoring dark pool vs lit exchange flow can help contextualize institutional execution patterns and liquidity conditions.
How often is the stock whale data updated? ▼
The dataset is refreshed on trading days and aggregates whale activity over a rolling lookback window of the previous 5 trading days. The dashboard shows the lookback date range for transparency.
Should I trade based on whale prints alone? ▼
No. Whale prints are one input among many. Large trades can be hedges, index rebalances, or execution of existing orders. Use this tool for context and validation alongside fundamentals, technicals, and risk management.
Important considerations
- Not all whale prints are directional — large trades may be hedges, rebalances, or execution of existing orders.
- Direction estimates can be wrong — treat the Lee-Ready output as probabilistic and validate with other signals.
- Context matters — consider earnings, macro events, and broader market conditions.
- This is not financial advice — use this tool for context and research acceleration only.
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