The U.S. dollar, favored as a safe place to store reserves in times of trouble, has risen to its strongest value in 20 years against other currencies and is expected to strengthen further, but that strength is weakening markets and economies around the world.

A Morgan Stanley analyst said the growth of the U.S. dollar is setting the stage for a crisis and something’s going to break.

The dollar is considered strong when it rises in value against other currencies in the foreign exchange market. As the U.S. dollar has risen, equity markets that rely on cheap currency have fallen, and there are growing fears that the dollar will hurt corporate earnings.

A strong dollar makes foreign travel less expensive for U.S. tourists and U.S. consumers benefit from cheaper import prices. But cheaper import prices are disinflationary and hurt profits. U.S. companies that export or rely on global markets for most of their sales have also been hurt.

“Such US dollar strength has historically led to some kind of financial/economic crisis,” said Morgan Stanley equity strategist Michael Wilson and other analysts in a client note.

On Monday, the U.S. dollar rise helped bring the British pound to a record low against the dollar, sending stock market averages down and bringing on more criticism of the U.S. Federal Reserve and other central banks.

The overriding reason for the strong dollar is the fight against inflation, according to NPR. The Fed is raising interest rates to slow inflation with more rate hikes expected this year. As it continues to raise rates, the dollar will strengthen.

“What’s amazing is that this dollar strength is happening even as other major central banks are also tightening monetary policy at a historically hawkish pace,” Wilson wrote. “If there was ever a time to be on the lookout for something to break, this would be it.”

Morgan Stanley estimates the S&P 500 will need to fall another 8-to-19 percent, or 3,000 to 3,400, to hit the floor and begin a turnaround, CNBC reported.

“The recent move in the US dollar creates an untenable situation for risk assets that historically has ended in a financial or economic crisis, or both,” Wilson wrote. “While hard to predict such ‘events,’ the conditions are in place for one, which would help accelerate the end to this bear market.”

Morgan Stanley’s currency team forecasts the dollar index, which measures the U.S. currency against other global currencies, to continue rising from the 114 index level, where it was trading Monday, to 118 by year’s end with “no relief in sight.”

“In our view, such an outcome is exactly how something does break, which leads to MAJOR top for the US dollar and maybe rates, too,” Wilson wrote. “However, until that happens, we think the screws will only get tighter for earnings growth and financial conditions.”