You can see why “Zuck” is going down this path. A third of the world’s population is now signed up to Facebook’s social media and messaging services. This has allowed Facebook to exploit users’ data to sell targeted advertising on a vast scale.

With its existing business model under threat, Facebook is looking for new revenue streams. And for inspiration it is looking at China.

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The name is unfortunate. Libra is latin for “pound”. In the last four years, the British pound has lost 25 per cent of its value against the US dollar. The Egyptian pound is down more than 50 per cent.

Here lies a problem. Facebook hopes to avoid the wild swings in other cryptocurrencies like bitcoin, and to build trust in its own crypto, by backing libra with holdings of assets in major currencies like the US dollar.

In this sense, libra will resemble the Hong Kong dollar, whose monetary base is fully backed by US dollar-denominated assets.

But while the Hong Kong Kong dollar is pegged to the US dollar alone, libra will be pegged to a basket of major tradeable currencies, presumably including the euro, yen and pound as well as the US dollar.

This means the value of libra will fluctuate against other major currencies. For ordinary consumers looking to pay for stuff in libra, the result will be that the libra price of goods and services – for example, a cup of coffee – will vary from day to day.

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This alone will likely be enough to kill the new project. For libra to work, companies would have to begin determining the prices of their products and services in libra. And, to avoid volatility between revenues and expenses, they would have to pay their staff in libra.

But neither companies nor workers would want paychecks in libra. Both would still have to pay their taxes in national currencies, which would mean that they if they used libra they would immediately begin to suffer from exchange rate risk. The value of their libra income could fall relative to their tax liabilities.

In short, no one would want to use libra, because the moment they did, they would open up a gaping hole in their accounts.

Imagine as a US investor you bought US$10,000 worth of libra, and by great good fortune the value of the other currencies in the basket rose relative to the US dollar, the value of your libras would increase, say to US$12,000.

Now imagine you wanted to buy a speedboat. You would have to sell your libras for US dollars. As far as the US revenue service is concerned you would have to pay a capital-gains tax on the increase on the US dollar value of your libras.

This suggests the real problem with libra. Governments might talk up the merits of competition, but in reality they cannot tolerate competitors.

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Libra might be a good idea, but not enough people will use it, because the inertia attached to existing national currencies is too great. If you have liabilities in US dollars, you will target revenues in US dollars to pay your creditors. You don’t want revenues in libra.

Ultimately, libra is not the competitor to central banks that boosters claim. In reality it poses no threat at all to established payments systems. Governments will lean heavily against it as a potential competitor. And consumer spenders will have little incentive to take it up in preference to their existing choices. Zuck will have to try harder. ■

Tom Holland is a former SCMP staff member who has been writing about Asian affairs for more than 25 years