Recaps · September 15, 2026
TPST, September 15: a quiet day, then $1.71 after hours
- Small cap
- Momentum
- Main move: after hours
- Catalyst: licensing option
- Thin regular session
- 8-K filing
- After-hours run
- Float
- 8.33 million shares
- Volume
- 12.35 million shares
- Previous close
- $0.7843
- Open
- $0.7990 (up 1.9%)
- High
- $0.8110 at 6:26 a.m.
- Close
- $0.7432
The day before
On September 14, TPST traded between $0.75 and $0.83. The official previous close was $0.7843. It was a low-volume stock: 71,061 shares traded that day.
Pre-market: very thin
The first trade came at 4:03 a.m. at $0.78. Most minutes after that had no trades at all, and many that did traded a single share.
The pre-market high was $0.811 at 6:26 a.m. Only 5,512 shares traded before the bell. That is a tiny number, even for a float of 8.33 million shares.
The regular session: a slow drift down
It opened at $0.799, then slipped to $0.77 within a few minutes. By 10:02 it was trading near $0.77, and by 10:35 it was at $0.75.
The low of the morning came at 11:16, at $0.7437. After that it turned up. It climbed through $0.78 at 11:44 and $0.79 at 11:49, and at 12:00 it printed $0.8082. That was just below the pre-market high, on 66 shares.
It could not hold. By 12:29 it was at $0.7664. Through mid-afternoon it traded between about $0.75 and $0.78.
Stop It's 3:52. The price is $0.7450. TPST opened near $0.80 this morning, bounced to $0.8082 at noon, and has drifted lower since on very thin volume, with long stretches where nothing trades. The morning low was $0.7437, and since mid-afternoon the stock has mostly sat between $0.75 and $0.76. The last trade at 3:50 was $0.75, and the stock is now a hair under that, near the morning low. Would you buy here?
Press play: the real Level 2, time and sales and chart stop at 3:52 p.m. ET for your call, then show what happened. The clip starts at 3:49 p.m. ET.
The low after the open came at 3:52 p.m., at $0.743.
The last regular-session trade was $0.7432 at 3:59, and 7,437 shares traded at $0.7554 in the 4:00 minute. Only 51,598 shares traded in the regular session. For most minutes of the day, nothing traded at all.
4:05 p.m.: the headline
At 4:05 p.m. GlobeNewsWire ran: “Tempest Secures Exclusive Option to License Clinical-Stage CD7-Targeted Lentiviral In Vivo CAR-T Platform.” At 4:06 p.m. the company filed an 8-K.
The 4:05 minute traded 5,303 shares and ran from $0.8157 to a high of $0.8969. By 4:09 it was at $0.98 on 89,117 shares in that one minute.
After hours: $1.71
It pushed above $1 at 4:17 and traded 240,434 shares that minute. Then came the top. At 4:23 p.m. it hit $1.71, the high of the day, on 840,212 shares in one minute. The same minute closed at $1.35.
It fell fast from there. By 4:26 it was back near $1.08. It bounced to $1.30 at 4:31, but that was well below the $1.71 top, and it touched $0.89 at 4:44.
After that it traded mostly between about $0.92 and $1.31. By 5:09 p.m., more shares had traded on the day than exist in the whole float (8.33 million). It closed the session at 8 p.m. near $1.26 after a spike to $1.35 in the last minute.
After hours, 12.3 million shares traded. The regular session had only 51,598. The whole day came to 12.35 million, about 132 times the stock's normal volume.
What to take from it
- The regular session gave no sign of the after-hours volume. TPST drifted from $0.80 to $0.74 on thin volume, and the real action came after the bell.
- The biggest volume came after the bell. The last regular-session trade was $0.7432 at 3:59, the headline ran at 4:05 p.m., and by 4:09 the stock traded $0.98.
- The first spike was the high of the day. $1.71 printed at 4:23 p.m., and nothing traded that high for the rest of the evening.
Replay this day
Trade TPST on September 15, 2026 yourself in Hindsight Markets: the real tape, the order book and the halts, on a clock you control, with fills from the real book.