Many countries don't recognize bitcoin and have no laws regarding it.
irrelevant
I'm sure you know that when you run a business you produce invoices, which serve as a proof of transaction for the client and the government (if needed). Do you make invoices when you mine bitcoins? I think not.
I'm sure you know that there are plenty of instances where you can receive a taxable gain but it doesn't involve you issuing invoices (to name a few: interest on deposits, fx gains, adsense revenue and alike, small-business low value online sales, tips of all kind... and bitcoin mining).
I specifically wrote that I meant business accepting bitcoins as a payment for goods/services and you're countering my point with bitcoin miners...
When a business owner decides to pay tax and he has no proof of transaction, he has to declare the amount he assumes is right, and I'll repeat assumes, because it's difficult to be accurate on such unstable grounds.
Take a moment and think about it. If we consider mining income what is his actual gain based on?
1. The price of bitcoin at the moment when it was mined?
2. The price at the time of filling up the income report?
3. Or, maybe at the time when he came to his farm and found out how much he has?
4. Or if he mines in a pool at the time when the coins appeared in his personal wallet?
5. Based on what exchange and what currency? In some countries there are no exchanges until this day, while in other you have to convert local currency to USD to perform a transaction. What about countries in which there's a discrepancy between the price in local currency and USD or the local price and the average.
You seem to think that there is some strict, rigid set of tax rules or guidelines that are supposed to cover every type of activity imaginable, and if your activity doesn't fall in any category - you're automatically exempt from tax (you're not). In reality, the criteria/time of revenue recognition can differ and can be tailored to your circumstances. Even businesses with similar operations can (and do) use different accounting policies.
In terms of large scale (non-hobbyist) miner, I'd say that most sensible approach would be to take the value of BTC at the moment it became available to you, ie landed in your wallet, or in your pool account, and if you have reasonable doubt whether your pool account will pay out, you could use the moment of successful withdrawal.
Same for valuation, you take the best rate that would be available to you (as if you decided to sell) at that moment. There's no one, set-in-stone, valuation method. Exchange rates swings between BTC/USD/your local currency are not that much of a problem, as you recognise (and offset) these separately in the accounts, either similar to fx gains/losses, revaluation, or asset impairment.
In terms of miners that hoard and won't convert to fiat - I wouldn't be surprised if (for practical reasons) they would be allowed to use one rate at the date of their financial year-end.
Point is, if you don't know how to calculate your taxes, you conduct activity that doesn't fall within any known category - then enquire with your tax office. The stupidest thing the business owner could do is to assume he's not liable to pay income tax because it makes sense in his head. "b...but I didn't know any better" is rarely a sufficient defence.
Again you said about business activity. Of course if you are allowed to register a business dealing in bitcoin you will be required to fill out a form each year, but that wasn't OP's question.
As long as we keep Bicoins as btc in our account and don't exchange them to either EUR or USD will we be liable for tax at this point?
Neither you or I know what OP really meant (he was likely just spamming), that's why I asked him to specify.
And my answer is still no. Until he exchanges it for fiat, goods or services, he doesn't have to report and pay anything.
1. There's nothing that links him as a person to his wallet account.
2. The value of the coins is so unstable, that one could say the sum of his yearly income becomes larger each month.
You're improving. Not that long ago it was only "fiat or a real estate" now you expanded to "goods and services". Still wrong though.
Last question, just for fun. If you were given an item of value, like an antique painting, and you knew you're not going to sell it so its value wouldn't matter to you at the time.
Would you go through all this trouble to find someone to price it, pay that person, fill out the tax form, and run to your tax office to report it?
If the type of gift was not taxable (ie inheritance) then the question is moot. You declare and pay capital gain tax upon the sale.
If the type of gift was taxable (or just declarable) - then I'd have to be clinically retarded not to declare it and pay tax if due. If I didn't and sold it X years later for a massive amount (attracting taxman's attention), I would not only have to pay overdue tax + penalty charges + accumulated interest on both (which could very well exceed the sale value), but I'd also be facing tax evasion charges.
So, just for a laugh, what would you do?
useful link (probably a bit out of date):
https://en.bitcoin.it/wiki/Tax_compliance