The phrase "major downturn" refers to a significant decrease or decline in something, such as the economy or a business. It suggests a significant drop or worsening of a situation. Full definition
Are you suggesting a passive investor would / should not have bought more of their index fund holdings during the last major downturn in late 2008 / early 2009? (financialwisdomforum.org)
The next major downturn in the market will be telling for the future of robo - advisors since it will be the first one that they face. (mybanktracker.com)
Recent investors might expect big swings in the market since their experience of major downturns had been the dot - com bust and subprime mortgage crisis. (knowledge.wharton.upenn.edu)