Broadly defined commodities surged over the five trading days through Friday, September 21, posting last week’s strongest gain for the major asset classes, based on a set of exchange-traded products. Foreign stocks in developed and emerging markets accompanied the commodities rally, delivering the second- and third-highest gains, respectively.

The iPath Bloomberg Commodity Total Return (DJP) popped 3.1% last week, marking its biggest weekly advance since April. Key factors in last week’s rally: perceptions that tensions are easing in the US-China trade war and a weaker dollar. The US Dollar Index slumped for a second week, closing on Friday near its lowest level since July.

Maintaining an upbeat outlook on commodities may become challenged anew this week, however, as the US and China impose new trade tariffs on each other today. Meantime, China says it’s calling off any trade negotiations with the US for now, a decision that threatened to raise economic tensions between the two nations.

“The trade war is now a reality,” said Brian Coulton, chief economist at Fitch Ratings. “The recently announced imposition of US tariffs on a further $200 billion of imports from China will have a material impact on global growth and, even though we have now included the 25% tariff shock in our GEO [Global Economic Outlook] baseline, the downside risks to our global growth forecasts have also increased.”

Last week’s biggest loser: real estate investment trusts (REITs) in the US. As expectations strengthened for another rise in interest rates by the Federal Reserve this week (the central bank’s policy announcement is due on Wed., Sep 26), rate-sensitive REITs took a hit. Vanguard Real Estate (VNQ) eased 0.4%, slipping to its lowest weekly close since early August.

The broad trend for assets overall, based on an ETF-based version of the Global Markets Index (GMI.F), remained positive. This investable, unmanaged benchmark that holds all the major asset classes in market-value weights edged up for a second week, gaining 0.9% for the five trading days through Friday.