Mark J. Terrill/AP
ITPro reports that Siilasmaa explained how the dealmaking process broke down four times and was looking more and more uncertain until, one Sunday night, he called up then-CEO Steve Ballmer and asked for a €2 billion (£1.4 billion) loan so that he and his team could buy the remainder of Nokia that Microsoft didn't want.
For those who are unfamiliar, Microsoft bought the devices part of Nokia (i.e. the Lumia brand), leaving Nokia Siemens Networks (NSN), the less well-known part of the business that manufactures data networking and telecoms equipment.
NSN was valued at €3.4 billion (£2.4 billion) but Nokia only had around €2 billion (£1.4 billion) on-hand and so Siilasmaa needed another €2 billion to make the deal happen.
According to Siilasmaa, Ballmer agreed to a loan of €1.5 billion (£1 billion) meaning that the deal could go through.
Microsoft recently took a write-down of more than $3 billion (£1.9 billion) on the Nokia deal while the value of NSN has multiplied 15 times in the past three years.