US benchmark equity indexes ended mixed Monday ahead of the reciprocal tariff announcements from the Trump administration this week.

* President Donald Trump will likely announce an average 15% reciprocal tariff, adding 9 percentage points to the effective tariff rate after exemptions, Goldman Sachs said in a note to clients.

"Along with tariffs imposed to date and sectoral tariffs we still expect, this would result in a 15 [percentage point] total increase," the investment firm said. Its previous estimate was a 10 percentage-point increase in the effective tariff rate.

* The Institute for Supply Management's Chicago PMI reading rose to 47.6 in March from 45.5 in February, higher than the expected 45 print in a survey compiled by Bloomberg but still indicating contraction in the sector. The sub-50 reading matches almost all the other regional manufacturing data already released for March. The national ISM manufacturing index for March will be released on Tuesday.

* May West Texas Intermediate crude oil closed up $2.13 to settle at $71.49 per barrel, while May Brent crude, the global benchmark, was last seen up $1.11 to $74.74 after U.S. President Donald Trump threatened to impose secondary tariffs on buyers of Russian oil as Vladimir Putin, his Russian counterpart, continues to violate a ceasefire agreement with Ukraine brokered by the United States.

* Newsmax (NMAX) debuted on the New York Stock Exchange, selling 7.5 million Class B shares at $10 apiece. Shares surged 722%.

* The shares of several vaccine makers, including Moderna (MRNA), slumped after Peter Marks, the US Food and Drug Administration vaccine chief, resigned late Friday, citing conflicts with Health and Human Services Secretary Robert F. Kennedy Jr.

Moderna was down 9.2%.