That was a biotech stock. They are very volatile. If he held long term he would've done much better. If you search for FDA catalyst dates, you can find dates when drugs are going to be approved or denied, etc. It's like a coin flip.
True, if Begich was a professional trader focused on biotech stocks, that behavior would be entirely normal.
But...the guy is a career politician from Alaska. What are the chances he suddenly decides to roll the dice on an obscure biotech stock 2 days before a positive piece of info drops?
You can see his other disclosures and its all mutual funds and blue chips.
Except Keryx hadn't yet applied for FDA approval of Zerenex, so the action date isn't relevant. On this day in question, they came out of the blue and announced their renal drug had surpassed expectations in a trial, so a U.S. senator buying them randomly the day before is suspect.