Kevin O'Leary sold his software company for $4.2 billion, so why did he only walk away with about $11 million?

Shark Tank 's Kevin O'Leary is known for making big deals, but one of the biggest of his career may have come with a much smaller personal payday than the headline number suggests. The deal illustrates why a company's sale price tells only part of the story for its founders and investors.

In 1999, Mattel acquired The Learning Company (TLC), the software company O'Leary helped build from the original SoftKey, in a stock deal valued at as much as $4.2 billion. Yet, a 2017 report by The Globe and Mail found O'Leary ultimately walked away with about $11.2 million. Still a fortune, but a fraction of the multibillion-dollar price tag.

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The biggest reason comes down to ownership. O'Leary held only a relatively small stake in TLC when Mattel came calling. TLC was a publicly traded company, so the multibillion-dollar price tag applied to the company as a whole, with shareholders receiving Mattel stock based on how much TLC stock they owned. O'Leary was one of those shareholders, not the sole owner.

An earlier Globe and Mail report suggested his $11.2 million take may have included nearly $6 million from selling most of the Mattel shares he received in the deal, along with up to $5.25 million in severance when he later left Mattel.

According to the Globe and Mail , the acquisition itself quickly went sour. Within months, TLC was losing money, contributing to a sharp drop in Mattel's shares, and O'Leary left about six months after the deal closed. Mattel CEO Jill Barad followed a few months later, and the toy company eventually unloaded TLC after the software division kept racking up losses.

Importantly, $11.2 million wasn't necessarily all O'Leary earned from TLC. The figure covers the Mattel deal and his departure from the company, not any salary, earlier stock sales, or other compensation he may have earned during his years at SoftKey and TLC.

O'Leary's experience with TLC isn't unique. Entrepreneurs often give up pieces of their companies as they raise money and bring on investors, meaning a big acquisition price doesn't necessarily translate into a dollar-for-dollar payday for the founder.