US stocks surrender early modest gains ahead of Jackson Hole

US stocks quickly surrendered early gains and drifted into negative territory, extending prior session's decline as investors gear up for the highly anticipated Jackson Hole Symposium. 

Investors remained cautious ahead of the very important speeches from the Fed Chair Janet Yellen and the ECB President Mario Draghi, which could potentially set the tone for global markets for the rest of the year.

At the time of writing, the Dow Jones Industrial Average slipped around 13-points to 21,799, while the broader S&P 500 Index fell 2-points to 2,441. Meanwhile, tech-heavy Nasdaq Composite Index trimmed nearly 10-points to 6,268.

Meanwhile, investors' sentiment remains weak in wake of the US President Donald Trump's threat on Tuesday to shut down the government to secure funding for a border wall with Mexico.