Softbank’s Arm IPO Highlights the Price of Not Sitting Still

SoftBank Group Corp. looks set to turn a tidy profit when it takes Arm Holdings Plc public sometime next week. While that’s nice, reality is the firm could’ve made more if it had just stashed its cash in an index fund and walked away.

The math is as follows. Masayoshi Son’s firm paid $32 billion to take Arm private back in 2016. Seven years later, the chip designer is set for a valuation of as much as almost $55 billion, good for a 70% gain over that period.

Now compare that to what other equity benchmarks have done ...