TikTok is facing unprecedented pressure over its ownership and business model after the U.S. moved ever closer to passing legislation that would force its China-based parent company to sell the platform or be banned.

Legislation that would force parent firm ByteDance to sell TikTok’s U.S. business within a year or face being banned in the country has passed through the U.S. Congress, and now only needs President Joe Biden’s signature to become law.

Here is a closer look at the troubles facing the social media giant.

What has the U.S. done?

The U.S. Senate has passed legislation that would force ByteDance, the China-based parent company of TikTok, to sell the platform within nine months, plus a three-month extension if a sale is in progress, or face being banned in the U.S.

The highly controversial legislation was included in a package of bills alongside foreign aid for Ukraine and Israel to help smooth its passage through Congress and onto President Joe Biden’s desk to be signed into law.

However, the bill is expected to face a fight from ByteDance, as well as extensive legal challenges from users and others before it is ever enacted.

Why have U.S. lawmakers done this?

The bill is the culmination of years of concerns expressed in the U.S. over possible Chinese government control of TikTok, and fears personal data from the app, which is used by around 170 million Americans, could be handed over to Beijing.

Officials in the U.S. have repeatedly expressed concerns that the Chinese authorities could force ByteDance to hand over U.S. user data or make attempts to influence app users by forcing the promotion of certain content on the platform.

TikTok has always denied that it is in any way influenced or controlled by the Chinese government, or that it would cooperate with any demands for data.

Are others concerned about TikTok?

Yes, the U.S. is not alone in raising fears about potential Chinese influence on TikTok.

A number of other governments, including the U.K., have banned the app from government devices over fears of Chinese influence.

The platform is also facing wider scrutiny over its business.

The EU is currently threatening to ban a new rewards program launched on the "Lite" version of the app in France and Spain, which pays users to spend time on the app.

European Commissioner Thierry Breton has called the feature "toxic and addictive," with the European Commission opening formal proceedings against TikTok to assess whether it has broken EU law.

Under new rules that came into force last year, the biggest platforms have to produce a risk assessment before they make major changes to their products.

What does all this mean?

TikTok users in the U.S., and particular creators on the platform, face potentially huge disruption to the service and their income streams should any ban ever take effect.

Critics of the ban say it violates a user’s right to freedom of expression by taking away a vehicle for it and have threatened legal action in response to the bill.

Many content creators and small businesses who rely on the site’s growing e-commerce platform would also see their income substantially impacted.

What remains unclear is whether other countries will follow the U.S.’ lead and also move to ban the app completely, potentially impacting access to the app elsewhere.

Even if others do not follow the U.S., the loss of its largest market would no doubt have an impact on the influence of the platform, with many American users likely turning to rival sites for their social media output and making it much harder for TikTok to compete.