For most of its nine-year history, bitcoin has been a financial-markets sideshow, sneered at as a plaything of criminals. No longer: 2017 is the year the digital currency stole the spotlight.

Why now? Part of it is pure momentum, which detractors say is a sure sign of a bubble: As bitcoin has climbed past each $1,000 milestone, it has spurred an investing frenzy. That reached a crescendo this week as the price jumped 40% in just 40 hours and pushed above $16,000.

But Bitcoin’s popularity also has been driven this year by a confluence of economic, financial and cultural developments. Regulators in countries such as Japan have given stamps of approval to trading bitcoin. Surging stock markets, along with continued declines in U.S. unemployment, have unleashed animal spirits, making investors hungrier for riskier plays. Wall Street is dabbling with the currency; futures contracts based on bitcoin are launching at two major Chicago exchanges.

Meanwhile, consumers have grown more comfortable with sending and receiving money digitally from their phones, even when a bank isn’t involved. This has made it easier for individual investors to pile into bitcoin and they, in turn, have pushed it into the cultural mainstream.

The singer Katy Perry recently posted a picture of herself on Instagram talking with Warren Buffett, and said she asked him about cryptocurrencies (she didn’t reveal his advice). CBS’s “Big Bang Theory”—the top-rated show on U.S. television—devoted a recent episode to a story revolving around bitcoin.