The earnings were good. Costco delivered $6.75 per diluted share on $93.9 billion in net sales Thursday night, clearing a consensus that had settled around $6.52. Net sales rose 11.2% and diluted EPS came in at $6.75 against $5.87 in the comparable quarter a year earlier. But the more interesting data point had already been filed with the SEC two weeks prior.

Five Costco executive vice presidents all reported acquiring shares on September 10, two weeks before Thursday’s report, as part of seven insider acquisitions totaling 29,749 shares over the past 90 days. Whether routine compensation-linked or not, the timing matters. And it is important to be precise about what happened here: at least some of these September 10 Form 4s reflect restricted stock units being granted or earned at $0, not executives writing open-market checks. Cluster activity at that scale, from that many executives, in the two weeks before a beat, is still a clean signal worth tracking.

The broader backdrop makes the contrast sharper. Corporate insiders sold $77.6 billion of stock during the first half of 2026, a 20% increase from a year ago, and the only time that pace was exceeded was back in 2021, when markets were flush with pandemic-driven stimulus cash. Insider purchases during the same period totaled just $6.9 billion, resulting in a sell-to-buy ratio exceeding 11-to-1. Against that backdrop, concentrated buying from any cluster stands out.

The scale of that selling wave is not a new phenomenon — it has been building across sectors for months. For more context on how insiders have been positioning ahead of major market moves this year, a closer look at the insider front-running pattern emerging across 2026 shows how the current cluster activity fits into a much larger behavioral trend.

The tech sector is the other side of this story. 28 executives at companies within the Technology Select Sector SPDR ETF (XLK) have purchased their own stock on the open market over the past six months, the highest count on record according to SentimenTrader, a figure that has doubled since the start of 2026. That surpasses the previous record of 25 insiders set in 2011, when in early 2025 just five executives were buyers. The buying is real cash, not options exercises, from people who understand product pipelines and capital allocation plans well before quarterly earnings reveal the full picture.

So which cluster is the stronger follow? Costco’s EVP activity confirmed something the stock already suggested: a business operating with structural advantages. Executive membership penetration reached a record high exiting fiscal 2026. Operating cash flow reached $15.825 billion in fiscal 2026, up from $13.335 billion the prior year. The weakness: Costco said $0.15 of the $6.75 EPS came from a non-recurring IEEPA tariff refund. Strip that out, the quarter is roughly $6.60, still ahead of consensus, just less emphatic. The stock did almost nothing, which tells you the market had already priced a good quarter at roughly 40x forward earnings.

The XLK cluster raises a different question. Amazon, Meta, Microsoft, and Nvidia insiders have not made open-market purchases in over two years, despite meaningful pullbacks in their share prices. That means the 28 buyers are concentrated in smaller-cap technology names, where executives have more room to move the needle with personal dollars and where the informational edge is larger. That is where the conviction is more actionable, not in the household names where insiders have been conspicuously silent.

The silence from Nvidia insiders in particular is worth examining in the context of what the company is navigating right now. Export policy uncertainty and Huawei’s accelerated chip timeline create exactly the kind of overhang that makes even well-informed executives cautious about committing personal capital — the China license situation and what it means for every semiconductor name this week lays out why that risk is still unresolved.

Celsius Holdings adds another layer. Celsius has had a rough year, plunging by almost 40%, but the CEO and two directors have put roughly $1.8 million into the stock this month. Revenue grew 11% year over year in the second quarter. That is a more complex situation, and complexity cuts both ways.

The pattern of insiders buying into a beaten-down story while the broader market remains skeptical is not unique to Celsius. It echoes the dynamic that played out earlier this year in enterprise software, where conviction from those closest to the business preceded a broader re-rating — how Palantir’s commercial pivot generated real revenue before the market fully believed it offers a useful parallel for evaluating whether early insider buying signals a genuine inflection or a value trap.

The verdict: the Costco EVP cluster validated a quarter that already came in. The stock at roughly $896 today is still about 18% below its 52-week high, with Wall Street’s average target near $1,089. The insider signal has been confirmed. The gap to target has not closed. For investors watching Form 4 filings this week, the XLK cluster offers the higher potential return, but Costco offers the cleaner, already-confirmed thesis.