4 If $SPX traded &lt;200d SMA for more than a month, it would be confirmed as "bear market"

5 In 2001-2003 &amp; 2008-2009 were recent confirmed bear markets as $SPX &lt;200d SMA

6 A key trend filter for systematic momentum strategy 

7 no longs if &lt; 200d SMA

8 no shorts if &gt; 200d SMA