Alphabet is raising $80bn in equity, an unusually large sum for a company that has rarely needed to ask. The Google parent announced the plan on Monday to help fund what it called investment in world-class AI compute infrastructure to meet unprecedented customer demand, and the structure of the raise is as telling as the headline figure.

It comes in three parts. The first is $30bn in concurrent underwritten public offerings, split evenly between mandatory convertible preferred stock and common and capital shares.

The second is a $40bn at-the-market programme, under which Alphabet will sell shares into the open market over time, expected to begin in the third quarter.

The third, and the one that catches the eye, is a $10bn private placement to Berkshire Hathaway, split between Class A common stock priced at $351.81 and Class C capital stock at $348.20, according to Alphabet’s filings.

The Berkshire piece is the detail that turns a financing story into something more interesting. Warren Buffett’s firm has historically been sceptical of richly valued technology and slow to write cheques into capital-hungry build-outs.