There may be some divided opinion among economists about the trajectory of the U.S. economy, but one thing they can agree on is that the tech sector—namely its investment—has been the engine driving U.S. growth.

Investors, whether they’re businesses or individuals, have had a lot to get excited about in recent years. The rapid development of artificial intelligence has reshaped expectations about how efficiently businesses can operate and what the working world will look like as a result.

But Wall Street has been here before, also with the tech sector. While the dotcom frenzy produced many of the household names we know today, it also proved to be a bubble with trillions of dollars wiped off market valuations.

Analysts are aware that overly bullish expectations may fall flat—even JPMorgan Chase CEO Jamie Dimon has warned some parts of the current investment cycle will ultimately prove to be in a bubble.

But new modeling from Oxford Economics suggests the popping of these expectations may prove to be a wrench in the works for America’s economy.