About 350,000 warrants of Digital World traded in the first two days. But on the third day — Oct. 4, a week after Digital World and Trump Media & Technology Group entered into formal talks that were not disclosed at the time — trading in the warrants exploded. More than 2.5 million changed hands that day.

The surge was unusual, especially for a little-known SPAC that hadn’t publicly identified a merger target, experts said. And with the Financial Industry Regulatory Authority now scrutinizing the merger deal — particularly trading activity that took place before the companies announced their agreement on Oct. 20 — warrants could be under a microscope.

“FINRA may see something in the high volume of warrant trading that makes it wonder whether something improper drove the volume burst,” said Erik Gordon, a law and business professor at the University of Michigan.