Cathie Wood's ARK Invest bought 154,521 Tempus AI shares on Oct. 30, a $12 million trade across two funds1.
Searches for the trade spiked the same week. The timing explains why. ARK bought right before Tempus reported its own quarter, and the two events now sit next to each other in the record.
A Trade That Topped Up a Stake
Tempus AI already held a top ARK spot before Friday. The trade only built on it.
ARKK's own disclosure put Tempus AI at 5.61 percent of the fund on Oct. 29, already third place behind Tesla and SpaceX2. Friday's buy built on that rank.
ARK paid an average of $77.84 a share for the new stock. That same session saw Tempus AI's price fall 7.2 percent and close at $72.227. The fund bought through that same drop.
Six Weeks of Selling, Then a Buy
The Friday purchase followed six weeks of ARK selling the same stock. Five separate sales ran from Sept. 14 to Oct. 281.
Those trades added up. ARK sold $5.4 million on Sept. 14, $6.9 million on Sept. 23, and $10.6 million on Sept. 29. Two smaller sales on Oct. 6 and Oct. 28 totaled $5.1 million more1.
ARK Sold $28 Million of Tempus AI, Then Bought Back $12 Million
ARK's disclosed Tempus AI (TEM) trades across its funds, Sept. 14 to Oct. 30, 2026, in millions of dollars
Each gray bar is a day ARK sold Tempus AI stock, the magenta bar is the Oct. 30 purchase, and the last bar is the six-week net change.
ARK's daily disclosures mix its ARKK and ARKG funds, so each bar is the combined trade across both.
Source: Cathie's Ark [1]. Chart by Ryan Elliott Dennis.
The numbers behind this chart
| Item | Value |
|---|---|
| Sept. 14 sale | −$5.4M |
| Sept. 23 sale | −$6.9M |
| Sept. 29 sale | −$10.6M |
| Oct. 6 and 28 sales | −$5.1M |
| Oct. 30 purchase | +$12M |
| Six-week net change | −$16M |
Add the sales and the Friday buy together, and ARK was still a net seller. The fund trimmed about $28 million of Tempus AI stock, then bought back $12 million of it. Six weeks of trading left ARK's funds about $16 million lighter in Tempus AI than where they started1.
What Tempus Told Investors Monday
Tempus AI filed its third-quarter results with the SEC two days after ARK's trade. The numbers beat Wall Street's math, and chief financial officer Jim Rogers walked analysts through them on the same day's earnings call.
Revenue reached $411.5 million, up 23 percent from a year earlier and past the $409.4 million analysts expected. Diagnostics testing revenue grew 20 percent to $303.5 million. Data and Applications revenue, the part of Tempus that sells patient data to drug makers, grew 33 percent to $108.1 million3.
Diagnostics Still Supplies Most of Tempus's $411.5 Million Quarter
Tempus AI's third-quarter 2026 revenue by segment, in millions of dollars, three months ended Sept. 30, 2026
The whole block is the quarter's revenue; the magenta share is Diagnostics testing, the blue share is Data and Applications.
Source: U.S. Securities and Exchange Commission [3]. Chart by Ryan Elliott Dennis.
The numbers behind this chart
| Item | Value |
|---|---|
| Diagnostics | $303.5M |
| Data and Applications | $108.1M |
| Whole | $411.5M |
"Q3 was another record quarter, as we delivered $411.5 million of revenue, led by accelerating unit growth of 32% in our oncology business and increasing momentum of 33% revenue growth in Data & Applications," said Eric Lefkofsky, Tempus's founder and chief executive3.
Tempus AI's net loss narrowed sharply too, to $14.9 million from $80 million a year earlier. Adjusted earnings before interest, taxes, depreciation and amortization climbed to $25.6 million from $1.5 million3. The company raised its full-year revenue forecast to $1.60 to $1.605 billion.
Lefkofsky tied the quarter to Tempus's wider pitch. "These results reinforce the durability of our model as our best-in-class diagnostic platform enhances our data and AI offerings, distinguishes our business from our many competitors, and helps drive our performance quarter after quarter," he said3.
The Bull Case Behind the Trade
Wood's Tempus bet traces back further than one Friday trade. She has argued for years that medicine, more than chat software, is where AI pays off biggest.
Cathie Wood, ARK's founder and chief investment officer, made that case on CNBC in February 2025. "We've got 37 trillion cells in our body, and they're going to be sequenced as we're looking for cures," Wood said4.
Wood's thesis treats a company like Tempus as a data business first. Every genomic test it runs adds a record to a pool it can license back to drug makers. That segment grew 33 percent last quarter3. Canaccord Genuity raised its price target on Tempus weeks before the earnings beat arrived, keeping its buy rating in place8.
The Bear Case Wall Street Still Holds
Some analysts read the same numbers and find doubt instead of proof. Jefferies has rated Tempus AI underperform since April, with a $35 price target that sits far under where the stock trades now.
The firm's concern centers on what insurers pay for Tempus tests next to competitors' versions. Jefferies wrote of an "unclear catalyst path in therapy selection, where peers have clearer upside through readouts, first-mover advantage towards CDx labels, and reimbursement"5. One rival's cancer test earns $8,500 from the government's MolDX program, against roughly $4,500 for Tempus's comparable test, Jefferies has noted.
Reimbursement risk sat underneath ARK's own selling through September and October. A fund cutting a position six weeks running was pricing in some version of Jefferies' doubt. Its founder, even then, kept making the public case for the opposite bet.
What to do
Read a fund's trade disclosures across weeks instead of one single day. ARK's own history shows a single Friday buy can sit inside a run of sales. The headline trade tells less than the six-week pattern around it.
Open the company's own SEC filing before trusting either side's price target. Tempus's Nov. 2 numbers are the record a reader can check line by line, apart from ARK's trade or Jefferies' rating.
Watch where the reimbursement argument lands next. Jefferies ties its bear case to one specific insurance code. A reader can track that code the next time Medicare updates its payment rates.
By the numbers
- $12 million: ARK's Oct. 30 purchase of 154,521 Tempus AI shares, split between its ARKK and ARKG funds1.
- Third place: ARKK's rank for Tempus AI on Oct. 29, a day before the Friday buy, at 5.61 percent of the fund2.
- A 7.2 percent drop: how far Tempus AI's stock fell on Oct. 30, the day ARK bought, closing at $72.227.
- Five trades: how many times ARK sold Tempus AI stock between Sept. 14 and Oct. 28, for $28 million combined1.
- $411.5 million: Tempus AI's third-quarter 2026 revenue, up 23 percent from a year earlier3.
- A narrower loss: Tempus AI's net loss fell to $14.9 million, down from $80 million a year earlier3.
- $35: Jefferies' price target on Tempus AI, roughly half where the stock trades now5.
What to watch
Tempus shareholders vote Nov. 30 on the company's $1.5 billion deal to buy Personalis. The vote tests whether the acquisition adds revenue or just adds debt3. ARK's next daily trade disclosure will show whether Friday's buy starts a new accumulation or stays a one-time top-up.
Sources
- "ARKK Holdings of TEM," Cathie's Ark, checked Nov. 2, 2026, https://cathiesark.com/arkk-holdings-of-tem
- "ARKK Holdings List - ARK Innovation ETF," Stock Analysis, checked Nov. 2, 2026, https://stockanalysis.com/etf/arkk/holdings/
- "Tempus AI, Inc. - Form 8-K, Exhibit 99.1," U.S. Securities and Exchange Commission, Nov. 2, 2026, https://www.sec.gov/Archives/edgar/data/1717115/000119312526442619/tem-ex99_1.htm
- "Ark Invest's Cathie Wood says the most underappreciated application of AI is health care," CNBC, Feb. 4, 2025, https://www.cnbc.com/2025/02/04/ark-invests-cathie-wood-says-the-most-underappreciated-application-of-ai-is-health-care.html
- "Jefferies initiates Tempus AI stock with underperform rating," Investing.com, April 13, 2026, https://www.investing.com/news/analyst-ratings/jefferies-initiates-tempus-ai-stock-with-underperform-rating-93CH-4609332
- "Tempus AI," Wikipedia, checked Nov. 2, 2026, https://en.wikipedia.org/wiki/Tempus_AI
- "Tempus AI (TEM) Stock Price & Overview," Stock Analysis, checked Nov. 2, 2026, https://stockanalysis.com/stocks/tem/
- "Analyst Canaccord Genuity Group Forecasts Strong Price Appreciation for Tempus AI (NASDAQ:TEM) Stock," MarketBeat, Oct. 12, 2026, https://www.marketbeat.com/instant-alerts/analyst-canaccord-genuity-group-forecasts-strong-price-appreciation-for-tempus-ai-nasdaq-tem-stock-2026-10-12/
