A YouTuber's big stock win is drawing scrutiny, which is bad news for both Markiplier and GoPro if regulators take an interest.

• Markiplier bought about $9 million of GoPro stock shortly before a merger was announced, turning it into roughly $15 million.
• The timing looks awkward because GoPro was losing money fast and could plausibly have gone bankrupt within months.
• His own explanation — that he "knew they were up to something" — hints at contact with people inside the company, which would be a fraud problem if true.
• He also promoted a GoPro product with a discount code without labeling it an ad, the same disclosure failure that got Kim Kardashian fined.

Outlook: There's a real chance the SEC opens an investigation, given how public and how well-timed the trade was.