Wall Street's main indexes ended down over 1% on Tuesday as 10-year Treasury yields held their multi-year highs, with investors still wrestling with prospects for a long period of high interest rates and the economic fallout.

The Dow posted its biggest one-day percentage drop since March, while all three major averages ended at their lowest closing levels in well over three months.

Adding to investor anxiety was the potential of a partial U.S. government shutdown by the weekend, which ratings agency Moody's warned would harm the country's credit.

Benchmark 10-year Treasury yields have climbed to 16-year highs in the wake of the Federal Reserve's hawkish longer-term rate outlook last week.

"We continue to adjust to the higher interest rates," said Brad McMillan, chief investment officer for Commonwealth Financial Network.

"What you are getting is increasingly a sense that the market is overvalued. ... There's a real sense out there that this isn't sustainable, and buyers are being scared away."

The Dow Jones Industrial Average fell 388.00 points, or 1.14%, to 33,618.88, the S&P 500 lost 63.91 points, or 1.47%, to 4,273.53 and the Nasdaq Composite dropped 207.71 points, or 1.57%, to 13,063.61.

All 11 S&P 500 sectors ended lower. The heavyweight tech sector dropped 1.8%, while the rate-sensitive utilities and real estate groups fell 3.05% and 1.8%, respectively.

The CBOE volatility index, known as Wall Street's "fear gauge," closed at its highest level since May 25.

Megacap stocks that have propelled indexes higher this year dragged on Tuesday.

Amazon.com shares dropped 4% as the U.S. Federal Trade Commission filed a long awaited antitrust lawsuit against the online retailer.

Investors are focused on Friday's personal consumption expenditures price index for a fresh view of the inflation picture. This week also brings other data including on durable goods and second-quarter gross domestic product, as well as remarks by Fed policymakers such as Chair Jerome Powell.

In company news, Immunovant shares surged 97% after early-stage data from the drug developer's experimental antibody treatment exceeded analysts' expectations.

Declining issues outnumbered advancers by a 5.9-to-1 ratio on the NYSE. There were 37 new highs and 388 new lows on the NYSE.

On the Nasdaq, declining issues outnumbered advancers by a 2.1-to-1 ratio. The Nasdaq recorded 35 new highs and 390 new lows.

About 10.2 billion shares changed hands in U.S. exchanges, in line with the daily average over the last 20 sessions. (Reporting by Lewis Krauskopf in New York, Ankika Biswas and Shashwat Chauhan in Bengaluru; Editing by Maju Samuel and Richard Chang)