* SpaceX IPO marketing materials inacessible, Reuters

review finds

* Cloudflare ( NET ) says rare block is likely a company decision

* Musk's China popularity contrasts with U.S. scrutiny

over alleged Chinese investment

By Summer Zhen and Kane Wu

HONG KONG, June 5 (Reuters) - SpaceX's website and IPO

marketing documents were not accessible on Friday in Hong Kong

and mainland China, a Reuters review showed, a step that

threatens to curb participation by investors there in a listing

expected to be the world's largest.

Elon Musk's SpaceX aims to raise $75 billion, the

most globally in an IPO, in a deal that would value the company

at $1.75 trillion, immediately vaulting it into the ranks of the

10 most valuable U.S.-listed firms.

The company kicked off marketing roadshows on Thursday in

New York and the IPO papers were posted on its website,

accessible to users in most major Asian markets, except for

mainland China and Hong Kong, the Reuters review showed.

Both institutional and retail investors access a company's

IPO marketing material to better acquaint themselves with the

business and financial details of such candidates, to ensure

they pick the best investment prospects.

Reuters could not immediately establish why and since when

the website of SpaceX, the rocket, satellite and ​AI company,

and the IPO material were restricted in mainland China and the

world's No.1 wealth hub of Hong Kong.

SpaceX did not immediately respond to Reuters request for

comment outside U.S. working hours.

Spokespersons for the IPO's lead banks, Bank of America ( BAC )

, Citigroup ( C ), Goldman Sachs ( GS ), JPMorgan ( JPM )

, and Morgan Stanley ( MS ), did not immediately respond

to Reuters requests for comment.

COULD BE FIRST U.S. MARKET DEBUT ABOVE $1 TRILLION

The SpaceX IPO has generated global interest and the listing

could become the first U.S. market debut in excess of $1

trillion, which would immediately make it one of the world's

most valuable publicly traded companies.

Besides a long list of Wall Street giants, Japan's Mizuho

and Macquarie Capital in Australia are involved in managing

SpaceX's IPO in Asia Pacific, the roadshow presentation showed.

An "Error 1009" message was displayed in response to

attempts to access the company website and marketing material

both in mainland China and the global financial centre of Hong

Kong, the Reuters review showed.

Web security provider Cloudflare ( NET ) said the most common

explanation for the error was that the website owner "has

banned" the country or region of the related IP address from

access.

Such a block is usually a company decision, said Francis

Fong, honorary president of the Hong Kong Information Technology

Federation.

While Hong Kong users have also been unable to access some

U.S. government websites in recent years, such cases are rare

for major companies, he added.

Musk is a household name in China, the world's

second-largest economy, where the success of his Tesla electric

vehicles makes one of the most popular foreign business figures.

In February, two Democratic U.S. senators urged the Pentagon

for an immediate review of SpaceX amid accusations that Chinese

investors had secretly acquired stakes in the closely held

rocket maker, citing potential national security risks.