MarketWatch Options Trader: This key stock-market indicator has switched to a ‘buy’ signal

The S&P 500 index broke out above its downtrend line on Oct. 14 and has been exploding to the upside ever since. It has now reached the all-time highs (4545), and the main question is whether it has enough energy left to break on out to new all-time highs.

If not, then the S&P SPX might be in a wide trading range between roughly 4300 on the downside and the all-time highs at 4545 (horizontal blue lines on the accompanying chart). There are several gaps on the SPX chart – all generated this week – and gaps are usually filled….