The Globe and Mail reports in its Monday edition that Nvidia's earnings report and the Federal Reserve's Jackson Hole symposium will test the assumptions behind this year's stock market rally, offering clues on whether the artificial-intelligence-driven surge in equities can withstand rising uncertainty over growth and interest rates. A Reuters dispatch to The Globe reports that global bond yields rose sharply last week, pushing the 30-year Treasury yield to its 2007 high. The Treasury Department's efforts to calm markets by doubling buybacks for long-dated debt offered only brief relief, with yields rebounding on Thursday, sharpening focus on the Aug. 27 to 29 event in Jackson Hole to see how Fed Chair Kevin Warsh communicates policy in an environment where guidance has been dropped. "All eyes are going to be pointed toward Jackson Hole because there's still not a whole lot of clarity. You see that with the bond market today," said Aptus Capital Advisors' David Wagner. The S&P 500 was down last week and about 2 per cent below its record high, as rising Treasury yields fuel worries about borrowing costs, weighing on semi-conductor stocks and dragging the Philadelphia chips index down 5 per cent for the week.