In This Article
Key Takeaways
- On July 20, 2026, Tempus AI (NASDAQ: TEM) and Personalis (NASDAQ: PSNL) announced a signed, board-approved Agreement and Plan of Merger, filing Form 8-K reports the same day. The deal has not closed.
- Personalis shareholders are to receive $16.25 per share — a 6% premium to the July 17 close, 28% to the unaffected 30-day VWAP, per the joint press release.
- It is a 100% stock transaction with an option for Tempus to pay cash for up to half the consideration, on a floating exchange ratio capped at 0.3356.
- Tempus already owned 12.5% of Personalis and has commercialized its NeXT Personal MRD test since a November 2023 partnership. Closing is expected in late 2026 or early 2027.
An AI health company is buying the laboratory that generates the data underneath one of its products. On Monday, July 20, 2026, Tempus AI and Personalis announced a definitive Agreement and Plan of Merger, approved by both boards, under which Tempus will acquire Personalis for $16.25 per share. Both companies filed Form 8-K reports with the SEC dated July 20. This is a signed and pending transaction, not a rumor and not a completed one — closing is expected in late 2026 or early 2027, subject to a Personalis shareholder vote and regulatory clearances.
What was announced, and when
Tempus, headquartered in Chicago, runs a precision-oncology platform built on sequencing and clinical data. Personalis, of Fremont, California, makes NeXT Personal — a tumor-informed assay that looks for circulating tumor DNA to detect residual or recurrent disease. The two are not strangers: the press release describes "the companies' existing partnership, established in November 2023, through which Tempus invested in Personalis and commercializes the company's NeXT Personal® MRD test." A Schedule 13D/A filed July 20 puts Tempus' existing stake at 13,039,067 shares, or 12.5% of shares outstanding.
(A note on terminology: the release's headline expands MRD as "Molecular Residual Disease" while its body says "minimal residual disease." Both appear in the same document.)
Tempus CEO Eric Lefkofsky framed the rationale around scale: "Through our existing collaboration with Personalis, we have already demonstrated the strength of combining highly sensitive MRD technology with our commercial infrastructure." Personalis CEO Chris Hall said the company was "confident Tempus' offer provides the most value to our shareholders and the fastest path to bringing Personalis' industry-leading tests to patients suffering from cancer."
The price — and three different totals
The per-share number is unambiguous: $16.25. The headline deal value is not, because three parties measured three different things. Attribute carefully.
The same deal, three published totals
| Figure | What it measures | Source |
|---|---|---|
| $1.5 billion | Total enterprise value, net of Tempus' existing ownership interest | Joint press release |
| $1.7 billion | Total transaction value before netting that stake | Tempus investor deck (Form 425) |
| $1.9 billion | Described as equity value for Personalis | Cooley LLP, counsel to Personalis |
Tempus' presentation reconciles the first two directly: the deal "results in a total transaction value of $1.7Bn ($1.5Bn net of Tempus' existing ownership interest)." Bloomberg headlined $1.7 billion; most trade coverage used $1.5 billion. The $1.9 billion in Cooley's announcement sits above $16.25 × 104.7 million shares, and we could not confirm how it reconciles — so we report it as published rather than explain it.
How the consideration actually works
Some coverage described this as a cash buyout. The filings say otherwise. Consideration is "structured as a 100% stock transaction with Tempus having the option to elect payment in cash at Tempus' discretion, capped at 50% of the consideration paid," with any cash portion funded from cash on hand and borrowings under existing credit facilities.
The exchange ratio floats. Per the Tempus 8-K, if the Tempus stock price — defined as the VWAP over the fifteen consecutive trading days before the last trading day prior to closing — sits at or below a floor of $48.42, the ratio is fixed at 0.3356. Above that floor, the ratio equals $16.25 divided by the Tempus stock price. Personalis gets downside protection: it may terminate if the Tempus stock price falls below a "Lower Floor Price" of $46.00, a right exercisable only in a narrow two-business-day window before closing.
Other terms from the filings: matching termination fees of roughly $76.8 million in each direction, an outside date of April 20, 2027 with two possible six-month extensions, and a voting agreement from Merck Sharp & Dohme LLC, which held approximately 13% of Personalis' voting power as of July 20. Neither company disclosed financial advisors; those, and the background of the merger, should appear in the Form S-4.
Announced is not closed
The merger agreement is signed and the boards have approved it, but the transaction still needs a Personalis shareholder vote and regulatory clearances, with an outside date of April 20, 2027. Until then, ownership of NeXT Personal has not changed, and the value Personalis holders ultimately receive moves with Tempus' share price.
Why it matters
The following is our analysis, separate from the reported facts above.
The detail worth noticing has nothing to do with oncology. Tempus is an AI platform company, and the asset it paid up for is not a model — it is the assay that produces the measurements the model reasons over. When the differentiating input to your system comes off someone else's instrument, that supplier relationship is a strategic dependency, and buying it is one way to resolve it. The same trade-off, at far smaller scale, is laid out in our build vs. buy decision framework.
The sequence is also instructive: partnership first in November 2023, commercialization through Tempus' channel, then acquisition nearly three years later with revenue and volume figures on the table. That is the opposite of buying a capability sight unseen — and it is a pattern worth recognizing whenever an integration partner becomes an acquisition target.
The diagnostic itself is a reminder for anyone building classification systems on faint signals: an MRD assay lives or dies on how it handles false positives and negatives at very low signal levels, the same tension our guide to precision, recall and false-extraction rate covers for text systems. Because it is clinical data, the governing constraints are the ones in building with regulated data. For another instance of health-AI consolidation this year, see UnitedHealth's $1.5B AI bet.
What happened next
Both stocks fell on announcement day. Bloomberg reported Tempus dropping as much as 9.2% to $47.65 and Personalis as much as 15% to $13.15 intraday; reported percentages differ across outlets because some cite intraday lows and others closing prices, so treat any single figure with care. A plausible reading, given the terms: the premium to the prior close was only 6%, and because the consideration floats with Tempus stock, Personalis shares track Tempus downward. Fierce Biotech and MedTech Dive both reported that analysts questioned Tempus' acquisition pace.
Ten days later, on July 30, 2026, Tempus reported second-quarter results: total revenue of $382.5 million, up 22% year over year, and net income of $5.6 million. It raised full-year 2026 revenue guidance to $1.595–$1.605 billion, with adjusted EBITDA of roughly $65 million — guidance that "assumes no impact from the Personalis transaction."
Deciding whether to build it or buy it
The question Tempus answered with $1.7 billion is the same one most teams face at much smaller scale. Our framework walks through when owning the capability is worth it — and when a partnership is enough.
Read the frameworkSources: Joint press release, Exhibit 99.1 to Tempus Form 8-K (SEC); Personalis Form 8-K, July 20, 2026 (SEC); Businesswire; Tempus investor relations; Tempus investor presentation (Form 425); Schedule 13D/A; Bloomberg; MedTech Dive; BioPharma Dive; Fierce Biotech; Cooley LLP; Tempus Q2 2026 results. Analysis and framing by Precision AI Academy.
Common questions
Is the acquisition final? No. The merger agreement was signed and announced on July 20, 2026 and approved by both boards, but closing requires a Personalis shareholder vote and regulatory clearances. The companies expect it in late 2026 or early 2027.
Is it a cash deal? No. It is a 100% stock transaction, with Tempus holding an option to elect cash for up to 50% of the consideration at its discretion.
How much of Personalis did Tempus already own? 12.5%, or 13,039,067 shares, per the Schedule 13D/A filed July 20, 2026.
How big do the companies say the MRD market is? They characterize it as a $20 billion opportunity — their own estimate, not an independent one.