Chinese smartphone maker Xiaomi awarded founder and CEO Lei Jun about $1.5 billion in stock, one of the biggest corporate paydays in history, The Wall Street Journal reported Friday.

The company gave Lei the stock to "reward him for his contributions" ahead of its IPO, The Journal reported, citing a document filed this week.

Xiaomi hopes to raise up to $6.1 billion in its Hong Kong IPO, which the Journal reported would value Lei's stock award between $1.38 billion and $1.79 billion.

A person familiar with the situation told the Journal that the award wasn't tied to future performance metrics and that it had been unanimously approved by shareholders. Lei has not previously received bonuses, the person added.

The practice of awarding founders extravagant stock packages is not uncommon — Tesla and JD.com both approved substantial stock-based compensation packages for their founders — but the Journal noted it is rare that a package is not predicated on a stock's performance.

Xiaomi's IPO will price next week, prior to the the company's July 9 listing in Hong Kong.

Read more about Xiaomi's CEO Lei Jun from the Wall Street Journal.