By Priya Raman

Elon Musk's SpaceX and Tesla together carry roughly $3.5 trillion in stock market value, more than Amazon, according to Trending Topics, and are only exploring a merger.

CNBC reported no agreement on the structure, terms or valuation. The figure therefore measures ambition, not a negotiated price. It cannot tell shareholders what they would receive. The control question comes first.

What does the $3.5 trillion headline mean?

A combination would rank among the largest corporate deals ever attempted, but SpaceX and Tesla already do business without one.

William Blair analysts questioned the strategic gain: “We are hard-pressed to find a material opportunity that could only be achieved by an official combination,” they wrote in a note CNBC reported.

The Amazon comparison also rests heavily on Tesla's market value, even as CNBC reported that Tesla's auto revenue is declining. The combined total reflects what investors pay for two stocks, not how well Tesla's car business performs.

Under the stock swap (an exchange of shares) under discussion, SpaceX would acquire Tesla rather than combine as equals, CNBC reported. For Tesla shareholders, the new company's size does not answer what they would own after the swap.

Which regulators can slow or stop the deal?

China accounted for 22% of Tesla's revenue last year, according to CNBC. JPMorgan analysts listed Chinese regulatory approval as a concern, as reported by TIME. China's regulatory scrutiny could therefore delay the transaction.

SpaceX's military contracts would bring national security scrutiny, alongside antitrust (competition review) and reviews in several countries, said Kevin Li, an analyst at Counterpoint Research in Beijing, according to CNBC.

Defense and competition officials in more than one country could therefore block the deal, alongside the two boards and their shareholders. Who negotiates, who votes and who can stop the transaction matter more than the companies' combined size.

How much independence does Tesla's board have?

Three of Tesla's nine directors have connections to SpaceX, according to Trending Topics. Those ties do not prove bias or bad decisions. They do mean outside shareholders cannot treat any eventual verdict as an arm's-length (independent) judgment between two separate companies.

Directors linked to SpaceX would judge an offer from the company they are tied to, and any price they endorse raises the question of which side it favors. Whoever negotiates must show that terms serve Tesla's ordinary shareholders. Their first check should be which approvers also answer to SpaceX.

Can Musk stay on the sidelines?

Musk runs both companies, so independent committees (director groups negotiating without him) are handling the talks, Trending Topics reported. Shareholders, especially Tesla's majority, must approve whatever they produce.

Musk has acknowledged that leading both sides keeps him outside those discussions. The committees have agreed no terms so far, so his step back has yet to demonstrate its value.

TIME reported Musk's comment: “I think it would be a good idea, but it's really up to the special committees of both companies.”

Who controls the shareholder vote?

• SpaceX: Musk holds around 82% of the voting power (the authority to approve corporate actions), enough to approve a transaction there alone, according to TIME.
• Tesla: Musk holds around 20%, allowing Tesla's other shareholders to outvote him and remain the only owners in the deal who can say no.
• Combined company: Under a Barclays estimate reported by TIME, Musk would hold around 56% of the voting power if SpaceX acquired Tesla. With no agreed structure, that remains one possible scenario.

Morningstar analysts Seth Goldstein and Nicolas Owens said the merger would let Musk manage every operation inside a single company with fewer governance (checks on management) obstacles. The oversight provided by committees and shareholder votes would be the very oversight a merger reduces.

If the Barclays estimate holds, a Tesla shareholder vote approving the merger could be the last in which Musk's fellow owners can outvote him.

What did investors actually think?

Tesla shares rose about 1.5% after hours but fell 3% on Thursday, CNBC reported. SpaceX shares fell 9% that day. Early cheer did not last.

Dan Ives of Yorkville Ives & Co called the combination a no-brainer, yet the market's next-day moves did not confirm sustained enthusiasm. The Amazon-topping total had added two stock values that fell the following day.

That market pricing does not establish an agreed value for a merged company. The unanswered issue is not whether the new company would rank among the world's largest. It is whether shareholders can constrain the man who sits on both sides of the deal.