STORY: SpaceX's website and IPO marketing documents weren't accessible in Hong Kong and mainland China on Friday.

That's what a Reuters review showed.

It threatens to cut participation by investors there in a listing expected to be the world's largest.

Bloomberg reported sources had said SpaceX's underwriters have barred investors in China and Hong Kong from taking part in the IPO.

It cited regulatory and compliance concerns.

Elon Musk's SpaceX aims to raise $75 billion in a deal that would value the company at $1.75 trillion.

That would make it one of the 10 most valuable U.S.-listed firms.

The company kicked off marketing roadshows on Thursday in New York.

It also posted its IPO roadshow materials on its website.

A Reuters review found they were accessible in most major Asian markets, except for mainland China and Hong Kong.

Investors access a company's IPO marketing materials to better understand their business and financial details.

Reuters couldn't immediately find why and since when the website of SpaceX and the IPO material were restricted in mainland China and Hong Kong.

SpaceX didn't immediately respond to Reuters' request for comment outside U.S. working hours.

The SpaceX IPO has global interest and the listing could become the first U.S. market debut in excess of $1 trillion.