(Updates with latest market prices and developments.)
US benchmark equity indexes were higher intraday, supported by gains in the healthcare sector amid a big rally in Moderna (MRNA) shares, while traders awaited minutes of the Federal Reserve's last policy meeting.
The S&P 500 was up 0.3% at 7,716.7 after midday Wednesday, while the Nasdaq Composite rose 0.2% to 26,341.6. The Dow Jones Industrial Average advanced 0.2% to 53,436.2. The indexes finished Tuesday trading lower for the third consecutive session.
Among sectors, healthcare paced the gainers, while industrials led the laggards.
Moderna shares were up 142%, the biggest gain on the S&P 500, as a late-stage trial for a skin cancer treatment being developed in partnership with Merck (MRK) yielded positive topline results. Merck jumped 11%, the best performer on the Dow and among the top gainers on the S&P 500.
Keysight Technologies (KEYS) was the worst performer on the S&P 500, down 6.3%. Late Tuesday, the electronics test and measurement equipment manufacturer provided a fiscal fourth-quarter earnings outlook above Wall Street's estimates and reported better-than-expected third-quarter results.
In other corporate news, Target (TGT) lifted its full-year outlook as tariff refunds helped double the retailer's fiscal second-quarter earnings year over year. Its shares were up 5.8% intraday.
TJX (TJX) issued a fiscal third-quarter comparable store sales forecast that fell short of the Street expectations, but raised its full-year earnings outlook. The stock fell 2.9%.
The Fed is scheduled to post minutes of its most recent policy meeting at 2 pm ET, which will be assessed for fresh insights on the central bank's monetary policy. At the meeting last month, policymakers left interest rates unchanged in a divided decision, with three regional presidents calling for policy tightening.
Markets are currently pricing in a 63% probability that the Fed will keep its benchmark rate steady in September, with the remaining odds in favor of a 25-basis-point hike, according to the CME FedWatch tool.
Treasury yields were mixed intraday, with the two-year yield up 1.3 basis points at 4.19% while the 10-year yield fell 4.6 basis points to 4.7%.
The Treasury Department said Wednesday that it will boost the size of its government debt repurchases to at least $4 billion per operation from $2 billion, effective Sept. 9. The buyback operation will focus on 10- to 30-year Treasuries.
West Texas Intermediate crude oil was up 2.3% at $86.87 a barrel intraday, while Brent rose 1.7% to $92.59.
The United Arab Emirates is halting all trade and financial transactions with Iran "until further notice" amid "regional escalations that undermine regional and international peace and security," UAE Foreign Ministry spokeswoman Afra Al Hameli said on X. The UAE is Iran's second-largest commercial partner, according to a CNN report.
"Oil prices extended gains for a fourth consecutive session on Wednesday as uncertainty over a resolution to the US-Iran conflict continued to support risk premiums," ING Bank said.
Spot gold jumped 3.7% to $4,495.25 per troy ounce, while silver climbed 3% to $65.96 per ounce.
