The last two months have been a tough one for the market, especially for the tech stocks that had been the leaders. Amazon, Facebook, Google and others fell hard while so-called "defensive" sectors (utilities, telecoms, consumer staples, etc.) held their own or rose.

Traders, hedge funds and many professionals had loaded up on tech stocks, so convinced were they that prices would rise without end. When so many investors are on one side, it's almost a certainty that the market will go the other way.It did.

The news background continues to support the bull market. The economy is growing faster than it has in many years, unemployment is low, wages and salaries are up 3.1 percent year over year (the biggest jump in a decade), inflation is still a non-event, and consumer confidence is at an 18-year high.Instead of moving higher, however, the market retreated, rallied, and retreated again. Why the swings?

The word "algorithm" has found its way into most market commentaries. An algorithm is a way to measure historical relationships between and among financial assets and take action when something is even just slightly out of whack. Algo traders buy one sector or asset class and sell another, then reverse positions seconds or minutes later. Algos cause and amplify the huge swings we now see. Watch the market and you'll see moves that are not due to knowledgeable investors weighing this point and that. They are the work of traders armed with algos that kick into action in a heartbeat.

To the media the catalyst for the market's swoon was the prospect of rising rates, underscored by Fed chief Powell's comments that rates are "nowhere near neutral" and four hikes through 2019 are planned. Prices immediately hit the skids. Some of the rate-sensitive sectors are already showing the impact of earlier increases. The auto and housing industries are two. At the very least the Fed should leave some wiggle room if data don't support three boosts in 2019. Better yet, take a break and see how things develop. If growth is slowing, and it is in some sectors, why slow it further when inflation is not threatening?

As for the bull market, it remains intact and only a recession could end it. That isn’t in the cards. Investors do need to prepare for more volatility, though. That is always true.