The “mother of all bubbles” is due to pop soon as U.S. outperformance has been inflated by massive amounts of debt, warned Ruchir Sharma, chair of Rockefeller International.

The U.S. has become too addicted to debt, and attempts to rein it in will eventually weaken economic growth and corporate profits, according to Ruchir Sharma, chair of Rockefeller International.

The market expert followed up his earlier “mother of all bubbles” warning with another column in the Financial Times last week that laid out how the bubble of U.S. outperformance versus the rest of the world will pop.

While Wall Street bulls point to strong earnings, Sharma said the record is less impressive after adjusting for government spending and the handful of tech giants with massive valuations, adding that “supernormal profits” tend to return to normal amid competition.

“Growth and profits are also getting an artificial lift from the heaviest deficit spending ever recorded at this stage of an economic cycle, by far,” Sharma, who authored the recent book What Went Wrong With Capitalism, explained.

Indeed, debt held by the public, or the amount the U.S. owes to outside lenders after borrowing on financial markets, is already at about 100% of GDP, with that ratio soon expected to blow past the all-time record set in the immediate aftermath of World War II. But this time, it will take place without a global catastrophe while the economy remains robust.