Microsoft large block option bet on Build conference catalyst

I've been a bit obsessed with watching $Microsoft(MSFT.US) options these past two days. Yesterday, the underlying stock rose 3.5% to close at $426.99, and it continued to climb to $427.69 after hours. But the options trade was even more shocking: the $440 Call expiring on 6/26 was swept up for $9.2 million, over ten thousand contracts, in a single day, making it the largest bullish trade of the session.

I looked it up: Microsoft is holding its Build conference next week, and The Information says they'll release a self-developed code model specifically to boost GitHub Copilot and serve as a low-cost alternative to OpenAI and Anthropic—in other words, Microsoft wants to prove it can compete without OpenAI. Choosing the $440 Call expiring on 6/26 perfectly covers the entire Build conference period. This is a bet on a catalyst, not a casual purchase.

Delving into the details gets even more interesting. Besides that major $440 Call, there was also a $427.5 Call (6/12) swept for $720,000 and a $420 Put (6/12) swept for $750,000 on the same day, straddling the current price with the same expiration. I'm thinking, this near-month pair of Call+Put looks like a straddle; institutions have laid down some short-term volatility protection for themselves before Build. But the main position is clearly that $9.2 million bullish $440 Call. The smaller Put looks more like insurance for that large long position, not a genuine bearish view. Overall, the Call side is nearly $10 million, while the Put side is only $750,000. I think the direction is clear: it's bullish.

The sentiment matches. MSFT's current IV is 38.8%, IV Rank 61, above median but not extreme. It's not cheap, but not outrageously expensive either. The Put/Call ratio is only 0.24 by volume and 0.47 by open interest, both well below the 52-week average of 0.7. Money is clearly leaning towards the Call side.

For most people: Going all-in on a far OTM Call like $440 is hard to stomach. Buying a single-leg Call with an IVR of 61 means watching time value decay painfully. But you could follow a scaled-down version—buy a $430 Call and sell a $450 Call to create a Bull Call Spread, lowering your cost with a cap at $450. The maximum loss is the net premium paid (the exact amount depends on real-time quotes when you place the order). If the price doesn't close above $430 at expiration, you lose it all. A suggested stop-loss is if the underlying stock breaks below $412—that's where this move started; breaking it would disprove the Build expectations.

Also, if you want to use Microsoft as a core holding and use LEAPS (long-term Calls as a stock substitute), don't get greedy with the strike price; don't go above 450. The current price is only 427. Choose LEAPS with strikes near the money like 430-450; they have high delta and will track the stock's movement well. If you go for cheap, deep out-of-the-money LEAPS like 500 or 550, they seem cheaper but have such low delta you won't make much even if the stock rises—you're just paying tuition in time value. With LEAPS, it's better to pay more for near-the-money than to touch deep OTM.

Of course, if what Build releases doesn't impress the market, or if the code model gets criticized as inferior to OpenAI's, that big $440 Call could still get stuck. But given the current risk-reward and directional bias, I think a slightly bullish tilt is justified. Only open one-third of your planned position size and decide whether to add more after Build actually delivers.