Hindsight Markets Small-cap stocks on September 15, 2026
GTBP on September 15, 2026: why it ran
On September 15, 2026, GTBP opened down 9.9% from the previous close of 11.63 and reached 13.47 at 8:50 a.m. ET. The exchange halted it once.
- Previous close
- 11.63
- Open, 9:30 a.m.
- 10.48
- Gap at the open
- down 9.9%
- Pre-market high
- 13.47 at 8:50 a.m.
- High, 4 a.m. to 4 p.m.
- 13.47 at 8:50 a.m.
- Low, 4 a.m. to 4 p.m.
- 8.16
- After-hours high, 4 p.m. to 8 p.m.
- 9.01 at 5:38 p.m.
- Last trade before 4:00 p.m.
- 9.07
- Volume
- 152,991
- Relative volume
- 5.0x
- Float
- 1.77 million shares, from filings as of September 15, 2026
- Shares outstanding
- 1.80 million
Why it ran
News and SEC filings for GTBP published between the previous session's close and the open, newest first, from the same feeds the replay shows.
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GT Biopharma Announces Potential New Indication for GTB-5550, a B7-H3-Targeted Natural Killer (NK) Cell Engager, for Multiple Myeloma
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8-K
News via Stock News API
How it traded
| Time (ET) | What happened |
|---|---|
| 8:50 a.m. | Pre-market high, 13.47 |
| 8:50 a.m. | High of the day to the close, 13.47 |
| 8:57 a.m. | SEC filing 8-K: 8-K |
| 9:15 a.m. | News (GlobeNewsWire): GT Biopharma Announces Potential New Indication for GTB-5550, a B7-H3-Targeted Natural Killer (NK) Cell Engager, for Multiple Myeloma |
| 9:30 a.m. | The open: 10.48, down 9.9% from the previous close |
| 9:30 a.m. | Halted: LULD pause (limit up-limit down). Trading resumes at 9:40 a.m. |
| 3:59 p.m. | Last trade before the 4:00 p.m. close, 9.07, 32.7% below the high |
The shape is a fixed rule, not a judgement: gapped 10% or more at the open, ran 10% or more from the open to the high, and faded if it gave back 30% or more of that move by the close.
The day in numbers
- Volume, from the one-minute bars: 27,441 shares before the 9:30 a.m. open (18%), 48,025 in the first 30 minutes (31%), and 77,525 in the rest of the day to 8 p.m. (51%).
- The halt at 9:30 a.m.: down 12.7% in the 5 minutes into it, reopened at 8.62, down 8.6% from the last trade before it, then down 0.2% over the next 5 minutes.
- Other days GTBP met the small-cap rule in our recaps: 2, the latest on September 14, 2026.
Halts
| Halted | Resumed | Length | Reason in the feed |
|---|---|---|---|
| 9:30 a.m. | 9:40 a.m. | 10 min 0 s | LULD pause (limit up-limit down) |
On this date the LULD plan ran under Amendment 18, in force from February 24, 2020: no band doubling at the open, and the closing doubling only for Tier 1 stocks and Tier 2 stocks whose previous close was at or below three dollars. See LULD halts or work out a band with the LULD calculator.
Trade this day
Replay GTBP on September 15, 2026 in Hindsight Markets: the real tape, the order book and the halts, on a clock you control, and see where your orders would have filled.