U.S. corporations are required to pay a one-time tax on their offshore profits, but don't expect those stockpiled funds to come onshore quickly—or ever.

Companies repatriated $169.5 billion in the second quarter, according to data released Wednesday by the Commerce Department, up from $34.9 billion a year earlier. Still, that followed a downwardly revised $294.9 billion returned in the first quarter.

The numbers for the first half of the year are just a fraction of the more than $3 trillion companies are estimated to have accumulated overseas to defer U.S. taxes on the money. President Donald Trump has said, without specifying his source, that he expects more than $4 trillion to return to the U.S., which will help to create jobs and more investment.