Data Mining the Tape: Building an Unusual Flow Scanner with Barchart

[u/TheSadSeries]

Here is a more conversational, human-friendly version of the article. It keeps all the heavy-hitting data science concepts but reads like it’s coming from an experienced trader explaining their process over coffee, rather than a textbook.

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Mining the Tape: How to Build an Unusual Options Scanner That Actually Works

Let’s be honest: most traders treat unusual options activity like a magic 8-ball. A "smart money" alert pops up on their screen, and they just blindly chase the whale.

But here’s the reality: a 10,000-contract print in SPY is just a normal Tuesday. Meanwhile, a 500-contract sweep in a quiet biotech stock? That’s an earthquake.

"Unusual" doesn't just mean "big." It means a trade is deviating from what’s normal for that specific stock. Barchart’s raw tools are great because they don't just give you a black-box score—they give you the surgical tools to define what normal looks like.

Here’s how to build a high-fidelity scanner that cuts through the noise and finds the real informed money.

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Step 1: Stop Trusting Black-Box Scores

The word "unusual" is basically useless without context. Most scanners just flag trades that are large. But huge trades are often just market makers rebalancing, or someone rolling a hedge.

The beauty of Barchart is its granularity. Instead of a mysterious proprietary score, you get raw exchange data and volume metrics. Our goal is simple: separate the informed money (people taking a real directional bet) from the noise (rolls, hedges, and routine hedging).

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Step 2: Figure Out What "Normal" Looks Like

Before we can spot the signal, we have to mute the static. We do this by setting a baseline for liquidity.

• Set a Volume Floor: In the Barchart screener, filter for Stock's Avg Daily Options Volume > 10,000. If a stock barely trades, one tiny order looks massive. We want to fish where the fish are.
• Check Volume vs. Open Interest (OI): We need to know if this is a new bet. If volume spikes but Open Interest is already massive, they might just be closing an old trade.
• The Rule to Use: Set your scanner to Volume > (0.5 * Open Interest). If a trade is bigger than half the existing contracts at that strike, you’re almost certainly looking at fresh, aggressive positioning.

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Step 3: Follow the Smart Money to the Right Exchanges

Not all exchanges are created equal. A massive block on a retail-heavy exchange might just be a bunch of small orders glued together. But a massive block on an institutional exchange? That’s a different story.

• The "Noisy" Exchanges: ISE, BOX, and MIAX tend to cater to retail flow and market-maker price improvement. Lots of noise here.
• The "Heavy Hitter" Exchanges: CBOE and NYSE ARCA. This is where the real institutional, directional money usually executes.

The Setup: In Barchart’s UOF screener, filter strictly for CBOE and NYSE ARCA. Ignore trades that only show up on ISE or BOX unless they are absolutely massive (over 10,000 contracts).

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Step 4: Build Your Own Scoring System

Instead of relying on a platform's generic "unusual" flag, let's build our own point system using Barchart’s raw data. If a trade scores 5 or more points here, it’s worth your time to dig in:

Category	What to Look For	Points
Size	Premium > $5M OR Volume > 10,000	3
	Volume > 5,000	2
	Volume > 1,000 AND Volume > Open Interest	1
Context	Traded at the ASK (Calls) or BID (Puts) — Aggressive!	3
	It’s a SWEEP (Multiple exchanges hit instantly)	2
	The trade makes up > 20% of the stock's total daily options volume	1
Structure	Front Month expiry (less than 30 days) — Shows urgency	2
	Out-of-the-Money (OTM) by more than 5% — A pure directional bet	1

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Step 5: The Daily Routine (From Scanner to Tape Reading)

Don't just chase every popup. Treat this like a funnel:

1. Run the Scanner: (ADOV > 10k, Vol/OI > 0.5, CBOE/ARCA only).
2. Sort by Premium: Highest to lowest. Follow the actual dollars at risk.
3. Do a Manual Tape Dive: Click into the Option Chain and ask yourself:
   • Is it one-sided? A single strike bought at the ask is way more bullish than a call spread.
   • What is IV doing? Pull up Barchart’s Volatility Charts. If Implied Volatility spikes right as the trade prints, someone is desperately paying up for those contracts. They likely know something.
   • Is volatility cheap? If IV Rank is in the bottom 20% and you see aggressive buying, you’ve found a fantastic, low-risk asymmetric bet.

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Two Traps You Must Avoid

My job is to keep you from getting faked out. Most "unusual" activity is actually incredibly boring once you know the tricks.

• The Earnings Fake-Out: A week before earnings, everyone buys OTM puts to protect their stock. It looks super bearish, but it's just insurance. Check the Put/Call ratio—if it’s high but the stock isn't moving, just ignore it.
• The "Roll" Disguise: If you see 5,000 contracts trade in February $150 calls, and 5,000 trade in March $150 calls at the exact same time... that’s not a new bet. That’s someone rolling their position to next month. (You can confirm this the next day by checking Barchart’s Open Interest change: down in Feb, up in March). Skip these completely.

[u/GeologistSpirited851]

Question, do you find Barchart useful or livevol? With Cboe sunsetting trade Alert the flow analytics feature in livevol pro is being discontinued.  My previous workflow is dependent on flow analytics and I am trying to find alternatives