Fri saw 2 DOW components get whacked hard bringing the Index down 300pts, that scared the bulls causing a contagion on the other Indices. EU somewhat escaped the sell-off so again performed better. The misfortunes of 2 companies, J&J & BOING, shouldn't cause a run, but, it can cause a wake-up call amongst the bulls, get them to take their profits as a herd and cause a significant sell-off. As the DOW closed at it's low, we need to see what happens on Monday or maybe next week as a whole as there is a food of reporting pending.
A note on the reporting. Everyone celebrates a beat on the reported earnings, "not as bad as feared" is the general comment, but that's the headline, a more significant factor is that the bar was set low and forward guidance is generally cautious i.e. not as good as the headline.
My view hasn't changed, I consider the markets overvalued based on PE numbers (see MARAMEO Post) v. the GDP, a ratio Mr Buffet uses. However, as another poster pointed out... markets can remain irrational for a very long time.