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.
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.