Tempus AI Rejected $70.90 on Heavy Block Selling — $61.60 Decides Who's Trapped Next

Deck: TEM ripped ~70% in a month, turned a real profit for the first time, and then Friday did the one thing a vertical chart fears most: it tagged a new high, reversed, and closed near the session low on heavy volume. The pullback is normal. Where it stops is not.

The collision

Friday was the chart event of the run. Tempus AI gapped down from Thursday's $70.69 close, clawed back to $70.90, and then the tape caved — the stock closed at $64.04, down 9.4%, near the session low, on 8.8 million shares worth roughly $580 million. Read the shape, not the headline: gap down, overshoot the prior close to fill it, then a hard rejection that left the day's chasers underwater.

That is a reversal, and it happened after the stock had already gone straight up for a month. The only question that matters now is whether Friday was the top of the move or the shakeout before the next leg — and that dispute resolves at a specific number, not on a mood.

How the rocket was built

Tempus stock climbed about 70% in a month, from roughly $41.55 on July 29 to the August 27 close of $70.69. This was not a drift. It was a stacking of catalysts on top of a heavily shorted stock.

The template came from a deal struck in late July: Tempus agreed to buy cancer-testing company Personalis for about $1.5 billion in an all-stock transaction at $16.25 a share, buying its way into minimal residual disease (MRD) testing — the business of detecting trace cancer DNA after treatment. The market initially read the price tag as dilution; shares fell roughly 9% the day the deal was announced. Then the story flipped. On August 19, Merck and Moderna said their Phase 3 melanoma trial of a personalized mRNA cancer therapy met its recurrence-free survival endpoint, and traders connected that validation to Personalis' sequencing work. Tempus surged about 24% in a single session that day. Along the way it piled on FDA wins — an August 24 clearance for an AI tool that flags pulmonary hypertension from standard ECGs, plus approval of its xT CDx companion diagnostic, which management says should add an estimated $85 million in annual revenue starting in 2027.

The fundamentals had momentum under it: Q2 revenue rose 22% to $382.5 million, and the company posted its first quarterly GAAP net profit — about $5.6 million — while raising full-year guidance.

Friday in volatility units

Size the move before reacting to it. Tempus' one-day volatility over the past month has run near 7.7%, with a 14-day ATR of about $4.74. Friday's 9.4% loss inside a 10.1% intraday range is therefore roughly double the tape's normal motion — an outsized session by this stock's own standard, not a routine wiggle in a splashy name.

And note what did not happen: momentum is only halfway unwound. RSI sits near 57 after the drop, not in oversold territory. There is technical room for this correction to keep going before dip-buyers get a statistically cheap price.

The more uncomfortable tell is who sold. The order-flow buckets for Friday's session show the largest-size orders — the block tier — as the biggest net sellers, with block outflows of about $32.8 million against $16.6 million of inflows. Smaller-size orders were net sellers too, but by less. Treat flow buckets as a signature, not a confession: they cannot name the seller, but a day that marks a high while the biggest order size is leaving is a distribution signature worth respecting. Everyone who bought into the $69–71 zone now owns a loss, and trapped inventory is exactly the fuel that accelerates the next leg — in whichever direction the resolution goes.

The line with memory

Everything now runs through $61.60.

That is not a round number invented from Friday's quote. It is the swing high Tempus set in early July — the ceiling the stock had to clear in August to convert a falling chart into a rising one. The market has already shown it will sell at that price once. When a level has done that, orders tend to cluster around it, which is why reactions there carry more signal than reactions anywhere else. Friday's low printed at $63.77, just above the line.

Up here, $70.90 is the new ceiling. A reclaim of that level on expanding volume turns Friday into a fakeout — a shakeout that sucked out the weak chasers before the next thrust. The fuel for that thrust still exists: roughly 22% of the free float was short as of mid-August — about 29.9 million shares with days-to-cover near seven — down from 33.9% at the end of June only because the run forced covering. Squeeze fuel makes a move possible, not guaranteed; a volume break above $70.90 would be the ignition.

Down here, the honest problem is distance. Close below $61.60 and the chart does not offer much until the big moving-average zone at $54–57 — the 50-day ($54.44) and 200-day ($56.56) sit within roughly 4% of each other, and that cluster is where the higher-timeframe trend itself begins. From Friday's close, that floor is about 11% away. Do not assume a bounce is cheap just because the stock is down 15% from the peak.

What traders are missing

The coil is two-sided, which is the part the headlines skip. The catalysts that built the rocket are now spent — the melanoma data, the FDA clearances, the earnings report are all in the tape. The next scheduled events, a Personalis close expected late this year or early next and the 2027 revenue uplift, are months away. So the near-term catalyst calendar is empty. That alone argues for a digestion phase.

But the short crowd never left. The squeeze that fueled the run was a covering event, not a full clearance — shorts still hold roughly a fifth of the float. That makes this a standoff with a defined referee: longs who chased $70.90 sit trapped above, shorts who waited for the reversal sit trapped below. The market is pricing a draw until price picks a side.

The map

Scenario	Trigger	Path	Invalidation	Horizon
Pullback extends	Close below $61.60	Air pocket toward $54–57 (50/200-day cluster)	Fast reclaim of $64	Days–weeks
Shakeout / consolidation	Holds $61.60, reclaims $63.8	Range-build $64–71	Loss of $61.60	Sessions–days
Squeeze resumes	Reclaim $70.90 on >2x volume	Toward the $75–80 zone	Second rejection at $70.90	Days–weeks

The verdict

Hold $61.60 and Friday was a pause inside a hot trend with squeeze fuel still in the tank. Lose it on a close and the trapped post-spike buyers fund a fast trip into the $54–57 demand zone. As of Friday's close, the evidence — a fresh-high rejection, block-size sellers, and a spent catalyst calendar — says the easy part of the move is done, and the order of the day is to let $61.60 tell you which exit is crowded before committing either way. Data as of the Friday, Aug. 28, 2026 close.