Stocks on Wall Street opened slightly lower on Tuesday after notching their longest rally this year, amid optimism that Jerome Powell will signal the Federal Reserve is open to a deeper cut when it starts lowering interest rates.

The S&P 500 (^GSPC) hugged the flatline, coming off an eight-strong run of daily wins for the benchmark index — its longest since November. The Dow Jones Industrial Average (^DJI) also traded flat, while the tech-heavy Nasdaq Composite (^IXIC) dropped about 0.1%.

Markets are marking time as anticipation builds for Fed Chair Powell's speech at the Jackson Hole get-together for central bankers at the end of the week. Stocks have made a strong comeback from an early August rout as fresh economic data bolstered the case for the central bank to start lowering rates sooner — and maybe further — than previously thought.

Wall Street expects Powell to set the stage for a September rate cut in dovish remarks on Friday, now that several Fed officials have given their blessing to easing. The debate now is whether a 0.5% cut is in the cards, rather than on the timing of the move, and what part upcoming labor data will play in deciding that.

On the corporate front, Lowe's (LOW) cut its annual profit and sales forecasts in its quarterly earnings before the bell. The home improvement retailer joined rival Home Depot (HD) in flagging muted consumer demand for big-ticket purchases.

In commodities, gold (GC=F) resumed its rally, climbing above $2,520 an ounce to hit another record high. The metal's price has risen over 20% so far this year as geopolitical conflicts and rate-cut prospects burnish the appeal of the safe-haven and non-interest-bearing asset.