Stock market seasonality is never an investment theme, and it can be a most difficult thing to trade.
With that out of the way, if this week turns out "bad" for stocks, know that that (last week of Sept. down) has consistently been the case (bigtime!) over the past 10 years. And of course the previous nine were not saddled with trade wars, etc.:
Take a look: click to enlarge...
Source: Bespoke Investment Group