It already has. It's just bounced off monthly resistance.
But besides this, how do you know it's the end of the rally? Surely the there must be more than one technical indicator?
Well you're right. A crossover of the and a break below the upward trending support would confirm this rally is over plus a dip below important MAs such as the 200 period.
What about the fundamentals? Isn't China and Euro free money investors buying up US stocks?
Well, this has probably contributed to the recent rally. Though if you're reading about it in the papers, the spending spree is most likely over. They aren't about to advertise their intentions and then act on it at a premium. I'd say Euro investors are going to be looking at Euro stocks as a priority. The US produced an excellent job report IMO but PE ratios but other economic data is poor meaning PE ratios are probably too high. I'd say Yellen will raise rates this Summer unless her mandate has shifted to propping up stocks instead of reducing unemployment.
Is the market in a bubble?
Yes, absolutely. Cheap money, has created excessive risk taking and ridiculous valuations. Id say we should be looking at a minimum 25% drop until the end of the 2017. Once the oil companies begin to close, that's when the poo will really hit the fan. I recommend reducing exposure to stocks. China is still very problematic and so is the Euro zone Yellen even is worried. One way or another, something's gotta give and the equity rally doing so well in a period of concern is suspicious. Either rates rise and the market falls, or PE ratios fall, or growth falls, or drop off. Either way, it can't continue much longer.