Tens of billions of dollars in financial assistance from the Chinese government helped fuel Huawei Technologies Co.’s rise to the top of global telecommunications, a scale of support that in key measures dwarfed what its closest tech rivals got from their governments.

A Wall Street Journal review of Huawei ’s grants, credit facilities, tax breaks and other forms of financial assistance details for the first time how Huawei had access to as much as $75 billion in state support as it grew from a little-known vendor of phone switches to the world’s largest telecom-equipment company—helping Huawei offer generous financing terms and undercut rivals’ prices by some 30%, analysts and customers say.

Huawei is vying to build next-generation 5G telecom networks around the world. While financial support for favored firms or industries is common in many countries, China’s assistance for Huawei, including tax waivers that began 25 years ago, is among the factors stoking questions about Huawei’s relationship with Beijing.

“While Huawei has commercial interests, those commercial interests are strongly supported by the state,” said Michael Wessel, a member of a U.S. congressional panel that reviews U.S.-China relations, in an interview. The U.S. has raised concerns that use of Huawei’s equipment could pose a security risk, should Beijing request network data from the company. Huawei says it would never hand such data to the government.

The largest portion of assistance—about $46 billion—comes from loans, credit lines and other support from state lenders, the Journal’s review showed. The company saved as much as $25 billion in taxes between 2008 and 2018 due to state incentives to promote the tech sector. Among other assistance, it enjoyed $1.6 billion in grants and $2 billion in land discounts.