The trigger for the worst day for US stocks on Friday was the disappointing economic readings from Europe, especially the powerhouse called Germany, with its manufacturing sector contracting for the third month in a row. The IHS Markit's flash euro zone composite Purchasing Managers' Index (PMI) (yes, I know it’s a mouthful) fell to 51.3 in March from 51.9 the previous month, when analysts were expecting a reading of 52.
(By the way, any number over 50 means expansions is still going on but it’s at a slower rate, and that German slowdown is the biggest worry out of these numbers.)
All this followed the Fed telling the market in the middle of the week that the US economy had lost a lot of oomph compared to what was expected, even as late as November last year. As a result, the two expected interest rates rises pencilled in for 2019 are more likely be none!