Donald Trump has vowed not to sell his Trump Media shares after a lock-up period expires Thursday. The company's shares are down 81% from their peak.

It’s a big day for Trump Media stock. The market is closely watching any move by Donald Trump and other big investors’ today as a lockup period that until now has barred any insider investors from selling shares expired.

Remember, Trump Media's primary fundamental is Donald Trump. It is why the stock, even at $15, sells well above a typical fundamental evaluation. Add in the stock's potential strengthening and the Trump brand could likewise strengthen.