While you were sleeping: Trump Jr shakes Wall St

Wall Street was mixed, recovering from an earlier decline amid fresh concerns about ties between President Donald Trump's administration and Russia.

The Dow Jones Industrial Average erased about 160 points in 20 minutes and volume in the most widely traded S&P 500 futures tripled as Donald Trump Jr released emails from last year about meeting a Russian prosecutor.

These showed Mr Trump Jr welcomed an offer of information that would "incriminate" Hillary Clinton and "would be very useful to your father" as "part of Russia and its government's support for Mr Trump."

At the close of trading in New York, the Dow Jones Industrial Average rose half a point to 21,409.07, while the Nasdaq Composite Index rose 0.3% to 6193.30 and the Standard & Poor's 500 Index slipped 0.08% to 2425.53.

"I think people are worried that it just means more political uncertainty, and sort of a continuation of the stalemate in Washington, a continuation of the delay in trying to get the Trump agenda passed through Congress," Robert Pavlik, chief market strategist at Boston Private Wealth in New York, told Reuters.

US Treasuries advanced, pushing yields on the 10-year note one basis point lower to 2.362%, while the greenback weakened.

Yellen to testify
Also, Federal Reserve Chair Janet Yellen is set to deliver her semiannual testimony to Congress, speaking before the House Financial Services Committee on Wednesday and before the Senate Banking Committee on Thursday.

"The semi-annual monetary policy testimony has often been a big deal for the markets," Scott Brown, chief economist at Raymond James in St Petersburg, Florida, told Reuters. "I think there may be some fears that she's going to come out relatively hawkish."

In the Dow, shares in General Electric and Boeing rose 1.2% and 1.1% respectively, outweighing falls in Nike and Pfizer, down 0.9% and 0.8% respectively.

Shares of Snap dropped 8.9% to $US15.47 after Morgan Stanley downgraded its rating on the stock as well as its price target, cutting the latter from $US28 to $US16. Morgan Stanley was the lead underwriter for Snap's initial public offering earlier this year.

"We have been wrong about Snap's ability to innovate and improve its ad product this year (improving scalability, targeting, measurability, etc.) and user monetisation," Morgan Stanley analyst Brian Nowak wrote in a note.

"Snap's ad product is not evolving/improving as quickly as we expected and Instagram competition is increasing."

In Europe, the Stoxx 600 Index ended the session with a 0.7% drop from the previous close. The UK's FTSE 100 Index fell 0.6%, France's CAC40 Index slid 0.5% and Germany's DAX Index slipped 0.1%.

(BusinessDesk)