By CHRIS BRYANT / Pic BLOOMBERG

ELON Musk’s decision to invest US$1.5 billion (RM6.08 billion) of Tesla Inc’s cash in bitcoin is financial dynamite that unites two speculative bubbles. There’s plenty to suggest the move is inadvisable.

Though small in the context of Tesla’s US$830 billion market value, this is still a material portion of Tesla’s US$19.4 billion cash reserves to park in such a volatile asset.

Tesla wouldn’t be the first car company to operate as a quasi hedge fund. For a time, Porsche AG made tons of money trading derivatives, almost bankrupting itself in the process. Owning cryptocurrency sits badly with Musk’s green ethos: Some bitcoins are mined with renewable power, but the industry still leaves a sizeable carbon footprint.

Musk’s purchase has boosted bitcoin’s price by almost 20%, so in one sense, he’s won already. Unfortunately, his bet won’t improve Tesla’s reported earnings or boost the value of its cash reserves. That’s because cryptocurrencies — despite the name — aren’t classified as cash or equivalents for accounting purposes.

Nor are they considered a financial investment under current accounting rules. Instead, they’ve deemed an intangible asset whose value is reported at cost in corporate accounts and must be written down if the price declines. The value cannot be written up again until they’re sold. This is a significant disadvantage and might dis- courage other corporate treasurers from following Musk’s lead.

It’s also not entirely fair, whatever you think about Musk gambling with Tesla’s money. Shouldn’t accounting standards be updated for the crypto era?

Here’s the relevant bit from Tesla’s 10-K:

Digital assets are considered indefinite-lived intangible assets under applicable accounting rules. Accordingly, any decrease in their fair values below our carrying values for such assets at any time subsequent to their acquisition will require us to recognise impairment charges, whereas we may make no upward revisions for any market price increases until a sale.

As we currently intend to hold these assets long-term, these charges may negatively impact our profitability in the periods in which such impairments occur even if the overall market values of these assets increase.

In plain English, if the price of bitcoin price suddenly fell by, say, a third compared to Tesla’s cost acquiring it — pretty plausible in the context of bitcoin’s historic volatility — then the carmaker’s GAAP (generally accepted accounting principles) earnings would be short US$500 million during that quarter.

Tesla will book no corresponding gain if the price rises again. The volatility of Tesla’s earnings could increase even more if customers start paying for their cars in bitcoin, as Musk will soon allow, and the company elects not to convert it immediately into US dollars.

This isn’t just a Tesla problem. Business analytics company MicroStrategy Inc invested a whopping US$1.1 billion in bitcoin as of Dec 31. It even decided to make bitcoin its primary treasury reserve asset, and so far the decision has paid off: Its holdings have almost trebled in value.

But because bitcoin’s price has fluctuated, MicroStrategy has already needed to book a total of US$71 million of impairments, including US$26.5 million in the fourth quarter.

The accounting treatment is weird because if you can buy a Tesla with bitcoin, then it’s clearly serving as a medium of exchange, albeit a volatile one that’s not state-backed.

Foreign currencies can be volatile too — just ask Argentina. There’s also a clearly observable market price for bitcoin as it’s traded on exchanges. In view of tentative efforts by airlines to accept cryptocurrencies as payment, the International Air Transport Association has argued that these tokens should be “treated as cash if they function as cash”.

Analysts will doubtless adjust Tesla’s reported financials to reflect the current value of its bitcoin holdings, but it’s an inelegant and less transparent approach. Unfortunately, the standard setters don’t appear to be in a rush to embrace the crypto revolution. The Financial Accounting Standards Board, whose job is to oversee GAAP, voted unanimously not to add cryptocurrencies to its technical agenda in October.

One can understand the reluctance. Accounting rules were created before cryptocurrencies were invented. The bean counters don’t want to be blamed if companies get their fingers burned.

Still, with interest rates at zero, I doubt Tesla will be the last tech company to try to earn a better return on its cash holdings. Anyone who does so is taking a massive financial risk, but they should be allowed to record the value of their bitcoin at the current market price. Anything else gives investors an incomplete picture. — Bloomberg

• This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.