Predictions for the opening bell were dire following overnight slumps in Europe and Asia. Japan’s Nikkei even entered a correction. U.S. equity indexes swung more than 900 points before 10 a.m. The benchmark for U.S. share volatility gyrated wildly after hitting a two-year high.

The most predictable selloff ever. That's what Federal Reserve Bank of St. Louis President James Bullard said of the latest market decline. Yesterday's sharp drop is tied to elevated valuations of technology stocks and the absence of any recent drops, he said. “So it is probably not surprising that something that has gone up 40 percent like the S&P tech sector would at some point have a selloff. Before there was a selloff, people said repeatedly some day this will sell off.” 

About that automated trading.You don’t need an engineering degree to tell something was amiss Monday. While it’s impossible to say for sure what was behind the Dow's 1,600 point nadir, the worst part of the downdraft felt to many like the machines run amok. For 15 harrowing minutes just after 3 p.m., a deluge of sell orders came so fast that it seemed like nothing breathing could’ve been responsible.

Not everyone wants Amazon in their backyard. Naysayers from the 20 regions vying for its new headquarters don't want to win. While mayors and governors compete to offer billions of dollars in tax breaks, these locals have no interest in paying the company to be a neighbor. Their communities are thriving, they say, and the online behemoth may end up diverting money from schools and other services, making housing unaffordable, clogging roads and straining transit.

A driverless future may upend real estate. The link between property and transport has been perhaps the most durable in human history. Few things have delivered higher land values with more certainty than advances in roads, canals, railways and highways. But now, the dawn of the driverless car—promising a utopia of stress-free commutes, urban playgrounds and the end of parking hassles—threatens to complicate the calculus for anyone buying property.

Brother can you spare half a trillion dollars? Cryptocurrencies continued to whipsaw investors on Tuesday, sending Bitcoin to its lowest level since October. Worries over tighter regulation by the U.S. and central bankers elsewhere gave traders fresh reasons to get out. The selloff has now knocked about half a trillion dollars from digital coins since early January. Ouch.

Jet engines used to be slung under a plane’s wing and then largely forgotten until they came in for a checkup. More recently, they’ve graduated to data downloads that allow engineers to devise maintenance regimes while aircraft are still flying. The next generation of turbines will be way smarter, and maybe even able to communicate with each other.