The rally in US markets has continued ahead of Friday's report, which is likely to reveal that the Federal Reserve's preferred inflation index is close to its target.

The S&P 500 index, which rose 1.0% on Thursday, is on the verge of an eight-week winning streak, the longest in more than five years, if it can hold onto gains. The Nasdaq 100 index, which jumped 1.2% following a round of selling on Wednesday, faces a similar struggle.

The VIX temporarily surpassed 14 for the first time since November, despite the fact that Wall Street's measure of stock volatility has been trading near multi-year lows.

The Fed's preferred inflation metric, the core personal consumption expenditures price index, is widely expected to hit the central bank's 2% objective when the report is released ahead of the opening of the US stock market on Friday.