Corporate fundamentals are good in the euro zone and the United States: But can fundamentals be used today to guide investment decisions?

When we look at corporate earnings , ratings and default rates in the United States and the euro zone, we see that corporate fundamentals are good. In particular , investment in US equities and in euro-zone corporate bonds seems to be consistent with the se fundamentals . But can fundamentals be used today to guide investment decisions ? Share prices have fallen and credit spreads have widened despite the se fundamentals, because of a rise in risk perception (due to protectionism, geopolitical tensions, political tensions in Europe) . Moreover , risk perception could continue to rise, for example if protectionism were increased .