Wholesale inflation picked up more than expected last month, indicating that mounting pressure on input costs will likely translate into higher consumer prices before long.

The stock market’s rally stalled on Thursday after new data showed factory-gate inflation picking up, introducing fresh question marks over the outlook for interest rates. Major indexes finished mixed and near the flatline after investors bought the shares of big technology and financial companies and sold smaller stocks that had surged earlier in the week.

The cost of wholesale goods and services — where rising inflation tends to show up first — posted the biggest increase in July in three years, possibly heralding a sizable acceleration in price increases tied to higher U.