If your employer has not deducted tax from you under PAYE and HMRC are unable to collect the tax from you via an adjustment to your tax code or other means, you may need to pay your own income tax directly to HMRC via Self click here for more Assessment. In this case, you should be aware that the usual deadline to register is by 5 October after the end of the tax year. This information does not constitute and is not intended to be a substitute for specific individualized tax, legal, or investment planning advice. Where specific advice is necessary or appropriate, Schwab recommends consultation with a qualified tax advisor, CPA, financial planner, or investment manager. While buying cryptocurrency alone isn’t a taxable event, the sale of a cryptocurrency qualifies as a taxable transaction.