U.S. stocks appear set for a weak opening on Tuesday as investors exercise caution after the Trump administration said more tariff letters could be sent out before August 1, according to White House Press Secretary Karoline Leavitt.

Stock index futures were largely flat on Tuesday, with the S&P 500 coming off a new record high, as attention remained on earnings, as some big tech companies are set to report this week. S&P 500 futures (SPX) and Nasdaq 100 futures (US100:IND) were flat,

U.S. stock futures showed slight gains on Monday, as investors braced for a busy week filled with earnings announcements from key S&P 500 companies. Verizon (NYSE:VZ) is expected to kick off the reporting season on Monday,

June inflation data released Tuesday represented an increase from May levels, despite the headline numbers matching expectations.

The Nasdaq is up 225.60 points or 1.5 percent at 15,587.25, the S&P 500 is up 45.12 points or 0.9 percent at 4,951.31 and the Dow is up 80.65 points or 0.2 percent at 38,600.49.

U.S. markets are on track for a higher open Monday, as investors digest growing optimism surrounding trade negotiations and brace for a wave of major corporate earnings. Futures linked to the Dow Jones Industrial Average,