STORY: Wall Street's main indexes ended mixed on Wednesday, as investors worried about escalating geopolitical tensions and a muted holiday-quarter sales forecast from Target.

The Dow ended up about a third of a percent, the S&P 500 finished flat, and the Nasdaq shed one-tenth of a percent.

Shares of Target plunged more than 21% after the retail giant forecast holiday sales and profits below Wall Street expectations--a stark contrast to Walmart, which a day earlier raised its annual sales and profit forecast for the third consecutive time.

Chris Konstantinos is chief investment strategist at Riverfront Investment Group.

"One retailer had really, really strong numbers and another retailer had very, very poor numbers and poor guidance. And so I think that that's confusing the picture a little bit. Then on top of that, obviously, the market is, I think, in general, trying to consolidate a lot of, not only post-election gains, but also just gains for the year, right? We've had a huge year-to-date number in U.S. markets. And so some of this, I think, is just excessive positive sentiment, trying to work itself off, particularly ahead of pretty big tech company reporting tonight."

U.S. stocks had fallen earlier in the session, after a report said Ukraine fired long-range British missiles into Russian territory. On Tuesday, Ukraine launched U.S.-made missiles into Russia, and President Vladimir Putin lowered the threshold for nuclear action.

Shares of Nvidia ended lower and then fell roughly 2% in extended trading after the chipmaker posted results after the closing bell.

It forecast fourth-quarter revenue slightly above estimates but still failed to meet lofty expectations of some investors who have made it the world's most valuable firm.