Deep in a $1 trillion pay package approved by Tesla's shareholders is an escape clause that could benefit Elon Musk if he merges the automaker with SpaceX. The clause would eliminate key performance targets, allowing Musk to receive billions in shares immediately.

Such a merger—the subject of investor speculation and hinted at by Musk himself—would likely give him tighter control over Tesla. A sufficiently high acquisition price would instantly remove barriers between Musk and his massive compensation package.

"This $1 trillion—that was supposed to be a stretch," said Mary Ellen Carter, a Boston College accounting professor. "It turns out it isn't really that hard. All you have to do be bought."

Musk's considerable influence over SpaceX means he essentially controls any offer made for Tesla. Even an extremely high bid would maintain his firm control over the combined entity, potentially unlocking his path to the unprecedented payday.