Tesla (TSLA) shares rose approximately 5% on July 6.
The rally increased the electric vehicle maker's market capitalization to $1.55 trillion.
Investor speculation regarding a potential merger with Elon Musk’s aerospace firm, SpaceX, drove the gains.
Market sentiment has shifted from whether a deal will occur to when it might happen.
Operational ties between the companies include SpaceX’s significant purchases of Tesla batteries and Cybertrucks.
SpaceX's recent IPO provides a framework for a potential stock-based transaction.