2014 was marked by a sense of hope that helped both sides of the market (debt and equity) make solid gains heading into early 2015.  Rates in the US were falling as the ECB fought to unveil true quantitative easing (and because they may have rebounded from late 2013 highs anyway, following the taper tantrum).  Stocks were in the midst of an unprecedented expansion, and economic data was improving fairly constantly.

In the first half of 2015, Chinese equities went parabolic, driven by a combination of a rapidly appreciating dollar and significantly cheaper oil.  The Shanghai index more than doubling in value from mid-2014 levels.  When the dollar stabilized at much higher levels, the crash was nearly as quick.  That got investors thinking that things might get worse again before they got better.  They looked beyond China and saw the proverbial "global growth concerns."  Here's how I put it on August 3rd, 2015 (before the last big leg of the Chinese stock sell-off, which also included the big domestic stock sell-off):

There's that phrase again: "global growth concerns"--that ridiculously broad concept that speaks to all of the more negative "what ifs" surrounding the global economy. What if European QE doesn't stoke growth and inflation? What if China is really in a downward spiral? What if the Fed's policy stance drove too much appreciation in the dollar, leading to a pull back in foreign investment and corporate profits among multi-national companies? What if a rising rate environment coupled with an appalling lack of wage growth kills any chance of domestic inflation?

After a dead-cat bounce to end 2015, rates began to move lower, ultimately hitting all-time lows by June 2016 (after the Brexit vote).  Since then, global growth concerns have been on hold as market participants look on in amazement and curiosity at the spectacle that is U.S. fiscal and monetary policy (tax bills, trade wars, our unique capability to hike rates when no one else can, and to do so while decreasing the Fed's amount of bond buying). 

Despite the spectacle, stocks surged.  At first it was the passage of the tax bill.  Then it was the hope that maybe the spectacle is actually going to work out.  Maybe, despite the avant garde policies and the length of the economic expansion, the good times could just keep on rolling.

Then October came along and it's been a rapidly-changing narrative since then.  Trade war re-escalations, Brexit re-escalations, Italian budget drama, corporate earnings deceleration, fear that front-loaded economic activity due to tariff fears would make for a bigger slowdown after the inventory-building, government shutdowns, housing fallout from rate spikes, you name it!  But it hasn't been until just the past few weeks that I've heard the phrase "global growth concerns" with any sort of noticeable frequency.  It's now getting hard to go a day without hearing it.

The most immediate example was the EU's updated GDP forecasts overnight that saw the bloc slowing to a 1.3% growth rate in 2019 vs 1.9% previously.  Germany's forecast fell to 1.1% from 1.8%.  These are HUGE changes and very much in line with some analysts' calls for negative German growth in the near future.  Combine that with an uncertain Brexit fate, a US government that will soon run out of funding again, a US/China tariff deadline that will pass without Trump and Xi meeting again, and it's not exactly a surprise to see the phrase making a comeback.  In the past, the phrase has been good for rates.  That was the case today, and it will continue to be the case as long as it continues to be an unsurprising part of daily market discussions.