Who are you asking ? Because no one knows the answer to this question and whoever thinks so, it's just one naive ignorant fool.
I've been waiting for this to uptrend to die and it refuses. Thought some months back this would be a slow death, slow rollover, but these days I'm thinking this bull market will continue for some while, as for a slow death, beginning to think when it finally goes it will be like jumping out the window. But like you say, we can only guess and just play each day as it's presented.
Every day it gets nearer but that doesn't tell you anything. Europe and emerging markets already had bear market in 2016 and are now expanding. Depending on what index you look at US avoided one and 2017 earnings now look good in next few quarters. Not really obvious to me why this bull should end any time soon.
An econometric data series that has foreshadowed portions of the largest, U.S. centric market declines has been the use / movements of the LEI . Undoubtedly, the economy ( underlying components of the leading index ) has an important relationship to earnings and stock prices, probably MUCH more than movements of HFT traders ( who may be able to move the market temporarily ). The use of a moving average heuristic ( trend following measure ) has helped with mechanical reentry / tilting back towards higher allocation of equity based assets. Both are objectively derived, non revised measures that together, have produced non trivial results towards risk management. tinyurl.com/n2ouhr4 ( paste links into browser address bar ) tinyurl.com/lfx7zhh Another variable that has shown statistical persistence in forward year predictive analytics, has been the strength of the 1st quarter returns of the S&P500. In 24 out of 25 occurences since 1951, the market has been higher 1 year out when the 1st quarter S&P500 return > 5%. None of these occurrences have had direct implication with the negative LEI periods shown. 1st qtr of 2017 = 5.7% .. From a tactical perspective, decent and meaningful equity market returns may be had by proper asset class selection, the growth of assets within a tax deferred account ( a Roth IRA is a good start ), and the avoidance of and protection of capital from a "portion" of the largest significant market declines. One doesn't have to try to get out at the top most or get in at the bottom most 'ticks", or try to trade every little squiggle. As the S&P500 has had positive annual outcomes 73% of the time and negative / flat outcomes 27% of the time ( since 1951 ), a decent tactical system based on long term time frame, may be invested in equity based asset some 85+% of the time and allocated to "defense" 15+% ... .... - Don't quit your day job - Don't use leverage - Open a Roth IRA - Sometimes money is made by sitting in cash - Don't be a hostage to the markets - let the markets, profitability of the world's economys work for you