A few years ago, while trawling for information about financial risk and where it might be held, I had a fascinating conversation with an economist at the US Treasury’s Office of Financial Research.

She told me to look at the debt offerings and corporate bond purchases being made by the largest, richest corporations, such as Apple or Google. In a low interest rate environment, with billions of dollars in yearly earnings, these high-grade firms were issuing their own very cheap debt and using it to buy up the higher-yielding corporate debt of other firms.

In the search for both higher returns and for something to do with all their money, they were, in a way, acting like banks, taking large anchor positions in new corporate debt offerings and essentially underwriting them the way that JPMorgan or Goldman Sachs might. Since such companies were not regulated like banks, it was difficult to see exactly what they were buying, how much they were buying, and what the market implications might be. Still, the idea that cash-rich tech companies might be the new systemically important institutions was compelling.