The latest #MacroMemo covers a lot of ground — the U.S.-Canada trade war, higher bond yields, investment booms and more. Here's what's on the radar: A new leg in the U.S.-Canada trade war. The U.S. applied a 50% tariff to about 5% of Canadian exports — roughly US$20 billion. Canada reciprocated with proportional tariffs effective September 8. What are the likely economic effects? Bond yields are climbing. The U.S. 30-year yield is nearing a 20-year high. The U.S. Treasury is doubling its bond buybacks to hold yields down. Will it work? Past investment booms often ended in a bubble. Of 11 booms we studied, six had bad endings. Will the AI capital expenditure (CapEx) boom be one of the good ones? Capital expenditures are broadening out beyond AI. Nearly half of S&P 500 firms plan to raise CapEx by 10% or more — the best number in decades, outside of a post-recession rebound. Is this the start of a broader investment cycle? Six months after the Strait of Hormuz closed, the oil market is holding together — but the cracks are showing. Normally 21 million barrels a day transit the strait. About 8 million of those are missing, although shadow fleets, pipelines and other tactics are closing the gap.What happens to oil — and inflation — from here? All this and more in the latest #MacroMemo video.