COST Options Signal: Heavy Put Wall at $900 vs. Bullish Block Trade

• Costco (COST) is trading near $904, testing a critical technical support zone.
• Options market shows a heavy concentration of Put Open Interest at $900 and $890, creating a potential magnet for price action.
• A notable block trade in long calls expiring Oct 30 suggests institutional confidence in a medium-term rebound.
• Recent earnings showed strong digital growth and membership retention, supporting a bullish long-term thesis despite short-term weakness.

It’s easy to get spooked when a stock like Costco dips, especially when you’re holding it for the long haul. But looking at the options chain right now tells a more nuanced story than just "red today." The market is essentially drawing a line in the sand at $900. On one side, you have a massive wall of put options betting on a drop. On the other, a subtle but significant block trade suggesting big money is positioning for a rise. Let’s break down what this means for your portfolio today.

The $900 Put Wall and the October Call Signal

When you look at the options activity for this Friday’s expiration, the sentiment is decidedly cautious. The Open Interest (OI) for puts is actually slightly higher than calls, with a Put/Call ratio of 1.036. This isn’t a panic, but it is a defensive posture. The most notable clusters are at the $630, $650, and $640 strikes, but here’s the kicker: there’s significant OI at $890 (876 contracts) and $900 (764 contracts).

Why does this matter? Because the stock is currently trading at $904. The $900 strike is essentially a psychological and technical floor. Market makers who sold these puts are incentivized to keep the price above $900 to avoid being assigned. This creates a "magnet" effect, where price action might gravitate toward $900 to test liquidity before reversing. It’s not necessarily bearish; it’s a test of support.

However, the more interesting signal comes from a block trade we spotted: COST20261030C905. This is a call option expiring on October 30, 2026, with a strike of $905. The volume was 10 contracts, but the turnover was $32,700. Why is this noteworthy? Because these are LEAPS (Long-Term Equity Anticipation Securities). Someone is buying deep-out-of-the-money calls for next year. They aren’t betting on a spike this week; they are betting that Costco will trade significantly higher than $905 in the next 13 months. This contradicts the short-term fear seen in the weekly puts. It’s a classic divergence: short-term traders are hedging or fading the dip, while long-term investors are buying the discount.

Earnings Strength vs. Short-Term Noise

The news flow supports the long-term bull case, even if the daily chart looks choppy. Costco’s recent Q3 fiscal 2026 results were, as analysts put it, "quietly excellent." EPS hit $4.93 on $70.53 billion in revenue. That’s an 11.58% year-over-year increase. But the real story is the stickiness of the membership model. Renewal rates are holding at 89.7%, and executive memberships, which drive 75% of net sales, grew by 9.6%.

There’s also a fascinating tailwind from the GLP-1 halo effect. As more people use weight-loss drugs like Wegovy and Ozempic, Costco is seeing increased sales in protein snacks and pharmacy products. This isn’t just retail; it’s a shift in consumer behavior that Costco is perfectly positioned to capture. Additionally, digital momentum is accelerating, with digitally-enabled comparable sales rising 21.5%.

So, why is the stock down? It’s likely a combination of profit-taking after recent highs and some broader market rotation. The short-term technicals are bearish, with the RSI at 37.89 (approaching oversold) and the MACD histogram negative. But the fundamentals are screaming strength. The disconnect between the strong earnings and the weak price action is where the opportunity lies.

Actionable Trading Opportunities

If you’re looking to trade this setup, you need to align your strategy with the time horizon.

For the stock, consider accumulating near the $900 support level. The 30-day moving average is around $943, but the current price is well below that. A bounce from $900 could send the stock back toward the $946–$947 resistance zone. If you’re conservative, wait for a confirmed close above $905 to ensure the put wall holds.

For options traders, here are two specific setups:

1. The Bullish Leap Play: Buy COST20261030C905. This aligns with the block trade we identified. It’s cheap because it’s out-of-the-money, but it gives you leverage if Costco returns to its $960+ range over the next year. It’s a low-cost way to bet on the long-term thesis.
2. The Weekly Income Play: Sell COST20260918P850. This put expires next Friday. The current price is $904, so this is a 6.5% downside bet. The open interest at $850 is 1,997 contracts, suggesting a strong support level. By selling this put, you collect premium if the stock stays above $850. Given the recent earnings strength and the $900 put wall, a drop to $850 seems unlikely in the next week. It’s a high-probability income trade.

Volatility on the Horizon

The market is currently in a holding pattern. The heavy put OI at $900 suggests that any drop below this level could trigger a short squeeze or a rapid rebound as market makers hedge. Conversely, the block trade in October calls shows that smart money is looking past this week’s noise.

For now, the trend is ranging, but the bias is shifting from fear to opportunity. If you can stomach the short-term volatility, Costco at $900 offers a compelling entry point for long-term investors, backed by strong fundamentals and strategic positioning by institutional traders. Keep an eye on $900 this week—it’s the line in the sand.