Sustainability is a new buzzword in our world. From my life experience, nothing is truly sustainable without change–sometimes massive–required to cope with external causes or even the forward march of human drive for improvements. We are experiencing a bull market for stocks that is approaching 98 months since March 9, 2009, when the mark-to-market accounting rule was tossed out.

This current 8 year trend is still more than a year shorter than that of late 1990 to early 2000, but it will end sometime. (If the SEC was to allow a guarantee in investing, it might be one that all uptrends are guaranteed to end. But we will have to check with the Commission for approval before I say that.)

When they do end, the next phase is usually not pretty. From First Trust of Wheaton, Illinois, (www.ftportfolios.com), we find that from 1926 through the most recent, the average bear market lasted 1.4 years and the S&P 500 lost a cumulative 41 percent. By the way, the positive news is that average bull markets for the same period provided a gain of 468 percent during a period lasting 8.9 years.

Why do bullish trends come to an end? Occasionally a horrendous external shock such as breakout of war can halt the advance, but far more often it is an interest rate increase leading to fear of recession. In my opinion, the present Federal Reserve Board Open Market Committee would all fall on their swords before they risked raising rates in a manner that would produce a true recession.

Are we in the next bubble already? Is this truly a Trump Bump which will become a Trump Dump if certain laws are not passed right now? My favorite economists, Brian Wesbury and Robert Stein, of First Trust Advisors, L.P., opine that the weak first quarter growth in real GDP (.7 percent) had several causes including the weather, both good and bad. However, Core GDP grew at a 2.2 annual percent rate and is 2.8 percent, right in the middle of the too-slow trend brought to us by the Zero Interest Rate Program of the Fed.

Under the big picture lie some hopeful developments. Business fixed investment rose to an annual rate of 9.4 percent, the fastest rate in four years. Home building grew by a 13.7 percent annual rate. Based upon demographics and the backlog caused by the Great Recession, they foresee a couple more years of housing recovery probable.

The real kicker to me is the growth in corporate profits. This is the best propeller of stock prices over any longer period of time. With about 300 of the S&P 500 having reported first quarter results, profits are higher than last year by about 15.6 percent. With consumer confidence back to new high levels, I believe that sales will also be growing at faster rates soon. We could be in a virtuous cycle for at least another year.

But as some of us joke, we could be only a tweet away from the start of the next bear market. But for now, the fundamentals don’t look too bad and are still improving.

(Past performance is no guarantee of future results. Advice is intended to be general in nature.)