Cathie Wood Tempus AI Stock Purchase: ARK Buys $12M

The Cathie Wood Tempus AI stock purchase took place on Friday, October 30, 2026. ARK Invest bought 154,521 shares of Tempus AI (NASDAQ: TEM) for about $12 million. It was the last trading session before Tempus was due to report third quarter results. This is a news report, not investment advice.

ARK split the trade between two funds, the ARK Innovation ETF (ARKK) and the ARK Genomic Revolution ETF (ARKG). The total came to $12,027,914, Investing.com reported from ARK’s daily trades.

That works out to roughly $77.84 per share. The average is our own math, not a figure ARK published.

Tempus was also the biggest buy on that day’s list. Next came Coinbase at $6.3 million and Circle at $6.0 million.

Meanwhile, the largest sale went the other way. ARK sold 17,626 Eli Lilly shares through ARKK, worth about $24.2 million, along with Bullish and CareDx.

This was not a one-way bet. Investing.com noted that ARK had sold Tempus shares earlier the same week, although it gave no size for that sale.

Here are the 2026 trades we could confirm. The list is not complete, since ARK trades this stock often.

Overall, the pattern looks like active position management. For example, ARK trimmed in September after a rally, Benzinga reported. Then it added again in October.

Still, that reading is ours. ARK has not explained this trade, and its daily disclosures only list what changed hands.

Indeed, the stock has moved sharply since summer. In July, TheStreet priced Tempus at $45.95, down about 22% for the year, in a report carried by Yahoo Finance.

In fact, part of that slide came from the Personalis deal. Tempus agreed to buy the company for $1.5 billion, paid mainly in stock, and the announcement weighed on the shares.

By September 1, Benzinga put the close at $62.27. It linked the surge to a Phase 3 trial from Merck and Moderna in personalized mRNA cancer treatment, which it said validated the Personalis purchase.

Based on our $77.84 average, the October 30 buy came about 69% above that July price. However, it still sat roughly 25% below the $104.32 record high from October 2025.

In short, it is large in both funds. ARK’s own holdings page, dated November 2, 2026, lists Tempus as the third-largest ARKK position at 5.73%, worth about $353 million.

Only Tesla and SpaceX rank higher there. In addition, Tempus is the top holding in ARKG at 8.50%, worth about $188 million.

Together, the two funds hold roughly $541 million of the stock. So a $12 million trade is an add to something already big, not a new position.

Tempus calls itself a technology company applying AI to precision medicine. In practice, it runs diagnostic tests for doctors and sells data and AI tools to drugmakers.

The second quarter shows that split. Diagnostics brought in $289.3 million, up 20%, while Data and Applications added $93.2 million, up 28%, its SEC filing shows.

Total revenue reached $382.5 million, up 22%. Tempus also reported $5.6 million in net income, although that included $98.5 million in unrealized gains on securities.

CEO Eric Lefkofsky called it “another exceptional quarter.” Moreover, the company delivered its first oncology foundation model to AstraZeneca during the period.

Tempus sits in a different corner of AI from the chip names behind most AI stock selloff headlines. Its numbers depend on test volume and data licenses.

Above all, timing is what makes this trade stand out. Tempus scheduled its third quarter report for before US markets opened on Monday, November 2, with a call at 8:45 a.m. ET.

So the Cathie Wood Tempus AI stock purchase landed in the final session before those numbers. Nothing in the disclosures connects the trade to the report, and that gap in time may be coincidence.

Going into the report, Tempus had guided to full-year revenue of $1.595 billion to $1.605 billion. It also expected adjusted EBITDA of about $65 million.

Update, November 2: Tempus reported its Q3 results that morning. Revenue rose 23% to $411.5 million, and net loss narrowed to $14.9 million from $80.0 million a year earlier. Adjusted EBITDA reached $25.6 million, up from $1.5 million.

By segment, Diagnostics brought in $303.5 million, up 20%. Data and Applications added $108.1 million, up 33%.

Tempus also lifted its full-year revenue guidance to $1.60 billion to $1.605 billion and kept its adjusted EBITDA outlook at about $65 million. In addition, the pending Personalis deal cleared regulatory review, and the Personalis shareholder meeting is planned for November 30.

Still, one quarter does not explain why ARK bought. This remains a news report, not investment advice.

A fund manager’s purchase is not a verdict on a stock. ARK also sold Tempus in September, and it sold the stock again earlier in the same week as this buy.

Similarly, Personalis is another open item. Tempus expects to close that deal in late Q4 2026 or early 2027, and it will be paid mainly in stock.

Finally, ETF trades can reflect fund flows or position limits as well as conviction. Without a statement from ARK, nobody outside the firm can say which applied here.

So far, the record shows one thing clearly. ARK treats Tempus as a core holding and keeps adjusting the size.

For the opposite mood in AI investing, read why Reuters says the China AI bubble has already burst. And for AI moving into the money business itself, see Claude for financial advisors.

Sources

Investing.com (October 30, 2026), Investing.com (March 26, 2026), Benzinga (September 1, 2026), TheStreet via Yahoo Finance (July 2026), ARK Invest ARKK holdings, ARK Invest ARKG holdings, Tempus AI SEC filing (July 30, 2026), Tempus AI SEC filing (November 2, 2026), Tempus AI press release (October 15, 2026). *Photos: Cathie Wood ARK Invest Photo by 3948wmc, CC BY-SA 4.0, resized and placed on a blurred background; Nasdaq MarketSite by ajay_suresh, CC BY 2.0, cropped and resized.*