Black Cross, from Kim Zussman
The 50D moving average of SPY may soon cross below it's 200D MA. Looking for instances when this occurred, AND it was the first downward cross in at least 20 days, found 6 instances since 1993. The following 5D tests bearish, but 10D and 20D are flat:
Date 5D 10D 20D
12/28/07 -0.042 -0.041 -0.077
10/01/98 -0.022 0.072 0.107
11/02/00 -0.019 -0.037 -0.073
04/29/94 -0.008 -0.013 0.017
08/25/04 0.002 0.012 0.003
07/25/06 0.004 0.006 0.027
avg -0.014 0.000 0.001
stdev 0.017 0.042 0.069
n 6 6 6
t -1.98 0.00 0.02