Speculation: My guess is this is being driven by the slowdown in China, and the very low price of petroleum. Startup funding, circa 2008-2015, was helped by the sluggish Western economies, the 1% interest rates, and the desperation investors had for yield. That era is over. But sluggishness in China is causing Chinese investors to look overseas, and they too are looking for yield. And also, it probably helps that oil prices are so low, as that both helps Western economies and also leaves all of the investors in the oil countries looking to invest in something other than oil. (In 2008, the price of oil briefly peaked at more than $140 a barrel. In recent years it has not gone above $50 a barrel for any sustained period of time.)