Updates with morning prices

By Johann M Cherian and Pranav Kashyap

March 11 (Reuters) - Wall Street's main indexes fell in choppy trading on Tuesday after U.S. President Donald Trump announced fresh tariffs on Canada, adding to investor unease that his trade policies could trigger an economic slowdown.

Trump doubled his planned tariff on all steel and aluminum products coming into the U.S. from Canada, bringing the total to 50%, in response to the province of Ontario placing a 25% tariff on electricity coming into the United States.

Global markets have been roiled ever since Trump sparked back-and-forth tariff moves against major trading partners such as Canada, Mexico and China. Analysts warn this escalating trade tension could fan inflationary pressures and potentially stall economic growth.

On Monday, the S&P 500 recorded its most significant one-day drop since December 18, wiping out a staggering $4 trillion from its recent peak. Meanwhile, the tech-heavy Nasdaq confirmed a 10% correction late last week.

"Every time we feel like we're getting a little bit of a lift, we get a Trump update on more tariffs ... it's getting ugly and it's going to hurt," said Dennis Dick, a trader at Triple D Trading.

"International investors looking at all the political uncertainty in the North American markets are saying let's invest elsewhere."

At 10:23 a.m. ET the Dow Jones Industrial Average .DJI fell 427.33 points, or 1.02%, to 41,484.38, the S&P 500 .SPX lost 34.54 points, or 0.62%, to 5,580.02, and the Nasdaq Composite .IXIC lost 33.70 points, or 0.19%, to 17,434.62.

All 11 S&P 500 subsectors fell, with cyclical stocks such as industrials .SPLRCI and financials .SPSY down about 1%.

Reflecting slowing consumer demand, Kohl's KSS.N forecast a bigger-than-expected drop in annual comparable sales, sending the retailer's shares down 19.9%.

Dick's Sporting Goods DKS.N declined 4.3% after the retailer forecast downbeat annual results.

Delta Air Lines DAL.N slid 6.2% after the carrier slashed its first-quarter profit estimates by half as CEO Ed Bastian blamed heightened U.S. economic uncertainty.

American Airlines AAL.O dropped 3.8% after the carrier forecast a bigger-than-expected first-quarter loss.

Meanwhile, a U.S. Labor Department report showed job openings increased in January. A closely watched inflation report is expected later in the week.

Interest rate futures point to the U.S. Federal Reserve leaving borrowing costs unchanged at its meeting next week, but they also have penciled in that the central bank could lower borrowing costs by at least 75 basis points by December on expectations of slowing growth.

Trump will meet the chief executives of America's biggest companies later in the day.

Megacaps were mixed, with Nvidia NVDA.O down 1%, while Apple AAPL.O lost 2.2%. Tesla TSLA.O added nearly 1% after the stock fell 15.4% in the previous session.

Oracle ORCL.N dropped 6.5% after the cloud company missed quarterly revenue estimates.

Citi became the latest brokerage to revise its stance on U.S. stocks, downgrading its recommendation to "neutral".

Despite the volatility, stock market valuations remain substantially higher than historical averages, according to LSEG Datastream.

Declining issues outnumbered advancers for a 1.36-to-1 ratio on the NYSE and a 1.31-to-1 ratio on the Nasdaq.

The S&P 500 posted four new 52-week highs and 10 new lows, while the Nasdaq Composite recorded 11 new highs and 174 new lows.

(Reporting by Johann M Cherian and Pranav Kashyap in Bengaluru; Editing by Shounak Dasgupta)

((johann.mcherian@thomsonreuters.com))