US Stock Futures Flat as Moderna Soars 96%, Treasury Yields Fall

US stock futures remained largely unchanged on Wednesday, August 19, as investors weighed several factors. The US Treasury Department announced plans to at least double its government debt buyback operations, which sent Treasury yields lower.

The 30-year Treasury yield fell nearly 9 basis points to 5.196%, while the benchmark 10-year Treasury yield declined 6 basis points to 4.647%. Lower yields provided some relief to stocks, particularly growth and technology shares, after rising borrowing costs had weighed on Wall Street earlier in the week.

Among individual stocks, Moderna surged 96% after the company and Merck reported positive initial results from a late-stage trial of their experimental personalised cancer vaccine. Merck shares gained 7%.

The Federal Reserve's July meeting minutes are expected to draw particular attention later Wednesday, providing clues on policymakers' views on inflation, interest rates, and the broader economic outlook.