The bond market rally is faltering and benchmark yields are rising - the result of strong economic recovery, rising inflationary pressures and expectations of tighter monetary policy.
Historically, such moves in bond markets have hinted at correction in equity markets - often the result of stretched valuations and expectations that future earnings cannot justify such lofty values.
What follows is a simple and - usually - regular function of financial markets: investors fear earnings will fall short of expectations, re-align their portfolios to favour bonds, sit back while the equity markets correct and then buy back into stocks when price/earnings ratios have fallen back to more reasonable levels.
A correction is when an asset, security or index falls 10% or more from its most recent cyclical peak. Corrections are common, and happen, on average, about once a year in equity markets.
The recent bull run in the US equity market has not been interrupted by a correction since January 2016, so it would appear that one is well overdue.
Equity valuations are looking lofty - particularly in the high-flying technology sectors that have seen the biggest gains in the past year or so. So why are equity markets continuing to break record ground?
"It is quite common for interest rates, government bond yields and equity prices to rise at the same time, so long as investors have a growing appetite for risk and a positive view of corporate earnings," says John Higgins at Capital Economics.
Indeed, data from FactSet show that out of the companies on the S&P 500 that have reported earnings so far, more than three quarters have delivered positive earnings surprises, while 81% have reported positive sales surprises - a record level.
On Tuesday this week, however, there was just a hint that the market was beginning to turn. As the US 10-year Treasury yield climbed more than 10 basis points in less than a week, equity markets fell sharply.
US indexes fell more than 1% before recovering some poise by the close, then Asian stocks were rocked, leaving the Nikkei 225 in Tokyo 1.43% lower. European stocks followed suit, falling more than 1% before recovering US markets helped mitigate some of Europe's losses.
Meanwhile, Europe's equity markets are being led lower on Thursday by Germany's Xetra Dax, down 1.4%.
A broad equity sell-off over just a couple of days is hardly an indication of a looming correction and a wholesale portfolio switch from risky stock markets to bond havens.