The fastest-moving whale trade we've surfaced this year started as a single line in the morning unusual options digest.
April 20, 2026. ARM Holdings (ARM) was trading at $172.10. Our Unusual Options Activity scanner flagged a buy on the ARM 170-strike call expiring March 19, 2027 — 3,000 contracts, $12 million in premium, paid at $42.00 per contract. The strike was barely in the money. The expiration was eleven months out. Whoever placed the trade was paying for a long-dated bullish view, defined-risk to the $42 paid.
Four trading days later, ARM's stock closed at $234.21. The 170-strike call closed at $95. Anyone who'd seen the print and bought the same strike on April 20 — or even just bought the stock — was sitting on the kind of move that would have made the year.
First published: Daily Institutional Flow Digest, April 20, 2026 · ARM flow on 2026-04-20.
The print
| Field | Value |
|---|---|
| Date | 2026-04-20 |
| Symbol | ARM |
| Side | BUY |
| Type | CALL |
| Strike | 170 |
| Expiration | 2027-03-19 |
| Volume | 3,000 contracts |
| Premium | $12M |
| Entry option price | $42.00 |
| Spot price at trade | $172.10 |
| Source-feed strategy tag | "Long Call" |
| Our classification | opening, VERY_HIGH confidence |
A few things worth noting:
-
Why ITM, not OTM. Buying a $170 strike with the stock at $172 means the trade has very little time premium decay leverage but maximum delta exposure. The institution wanted upside on the stock, not lottery-ticket convexity. They were paying $42 for the right to control 100 shares per contract over the next 11 months.
-
Why long-dated. Eleven months is enough to survive almost any single bad print or correction. The institution was willing to pay decay if it bought them a long enough window for their thesis to play out.
-
Defined risk. Maximum loss on this trade is $42 per contract — $12.6M total. Maximum gain is unlimited (the stock can keep going up). On a long call, you know your worst case before you put it on.
This print was visible on the /idea Unusual Flow tab on the morning of April 20. Anyone scanning whale trades that day saw it.
What ARM did next
Daily closes:
| Date | ARM close | Daily move | From 4/20 entry |
|---|---|---|---|
| 2026-04-20 (entry) | $172.10 | — | — |
| 2026-04-21 | $176.93 | +2.8% | +2.8% |
| 2026-04-22 | $197.50 | +11.6% | +14.8% |
| 2026-04-23 | $216.60 | +9.7% | +25.9% |
| 2026-04-24 | $234.21 | +8.1% | +36.1% |
| 2026-04-29 (today) | $201.69 | — | +17.2% |
ARM ran up about 36% in four trading days, intraday peak of $237.68 on April 24. Then today's session pulled back to $201 — still up 17% from the April 20 entry.
That kind of move usually reflects a specific catalyst (earnings reaction, partnership announcement, capacity guidance) and the move was concentrated in the first four sessions after the print.
What the option did
Sourced from Settled exchange tape:
| Date | 170C close | From entry |
|---|---|---|
| 2026-04-20 (entry) | $42.00 | — |
| 2026-04-21 | $45.00 | +7% |
| 2026-04-22 | $59.00 | +40% |
| 2026-04-23 | $67.00 | +60% |
| 2026-04-24 | $95.00 | +126% |
| Peak intraday | $97.02 | +131% |
| 2026-04-28 | $67.65 | +61% |
The 170-strike call more than doubled in four days and peaked at $97.02 on April 24 — a 131% return from the $42 entry. The stock pulled back today and so did the option, sitting at $67.65 (still +61% from entry). For an institution that spent $12M on the position, the unrealized P&L peaked north of $16M and is now around $7M — assuming they're still holding.
Multi-bagger options moves on individual mega-caps within four trading days are rare. They happen when (a) the institution has high conviction, (b) the catalyst lines up with the position, and (c) the implied vol entering the move was reasonable. ARM 170C 4/20 was all three.
What this trade did NOT mean
It would be dishonest to write a flashback like this without putting it in context. We aren't claiming we predicted ARM's rally. We aren't claiming the institution who put on the 170C had non-public information.
What this trade does show:
- A $12M institutional bet was placed on April 20.
- That bet showed up on the public options tape and was surfaced in our morning unusual flow report.
- The bet was structured for upside (long ITM call, defined risk, 11-month window).
- ARM stock and the 170-strike call both materially moved over the following four trading days.
The institution may have known something. They may also have just been right at the right time. We don't know which. What we know is that the print was visible — to anyone reading the unusual flow tape — before the move.
If you want the full context for how often this kind of pattern actually pays off, read the methodology piece. The honest answer: most institutional UOA prints don't go like this. Average returns are negative, win rates are roughly a coin flip on the unfiltered feed. The trades that work tend to share characteristics — defined structure, sized to the thesis, enough DTE to survive a chop. The ARM 170C 4/20 print fit those criteria. Most don't.
Closing the loop
The ARM 170C is still open in the institution's book — at least, our refresh_uoa_oi pipeline shows the contract's open interest is still elevated, suggesting the position hasn't been fully unwound. If the institution does close it, you'll see that print on the tape too.
When it does, we'll surface it.
See the live tape
This was one print. There are 12–24 like it on a typical day.
- /idea Unusual Flow tab — Browse today's whale trades. Articles 60+ days old are public; sign in for the past month; AIme Premium gets today's flow without delay.
- /idea/flow/digest — Daily Institutional Flow Digest published every market morning at 7am ET.
- /idea/flow/ARM — ARM-specific flow page (date-aware tier gating applies).
Upgrade to AIme Premium → AIme Premium subscribers read every UOA print the morning it ships, including multi-leg block trades, position-action classification, and per-leg open/close attribution.
Read more
- Whales Knew First: Three Trades That Moved Before the News — the original case-study series.
- INTC Whale Flashback: $57M Call Buy Six Weeks Before the Stock Doubled — different ticker, similar shape, bigger premium.
- How We Decode What the Whales Are Actually Doing — multi-leg strategy detection that turns raw prints into trade intent.
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