That means people with cryptocurrency holdings need to document that they own it, where they purchased it and how heirs can get access to it.

The problem, of course, is that the appeal to investors interested in crypto is its secrecy. No one will know if you have any bitcoin assets unless you tell them. That's great if you're planning to keep your wealth under the radar. But what happens if you die unexpectedly — and you haven't told your loved ones and heirs about your cryptocurrency stash?

It used to be that when someone passed away without a comprehensive estate plan, heirs simply had to watch the mailbox for 90 days or so to collect the different bank or brokerage statements that trickled in over time.

Things got more complicated with the advent of online banking and investing, because now you needed the deceased's email address as well as a password to access their account. These days you might even need to know if someone has an online lending account through an automated platform provider.

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Even if heirs didn't know about the existence of such accounts, they would eventually receive something from the Internal Revenue Service alerting them to unreported income from an overlooked account. It might take up to a year, but at least the surviving heirs would eventually learn about it.

There is, however, a document that can help alleviate this stress and avoid the waiting game. It's called the net-worth statement. It's basically a financial reporting document that details an individual's assets and liabilities — both short- and long-term.

Many people keep an updated list (often in a safety deposit box) of all their financial account information, along with a list of instructions for their heirs. Meanwhile, other people have begun using password-aggregation software as a way to securely keep all of their account information in a single repository, both as a backup and as a way to share that information with their heirs if need be.

Many believe that having the now-deceased account holder's login information will help them access the funds. Keep in mind that when an institution such as a bank or investment firm learns that someone dies, they will freeze those accounts until the estate-settlement process is completed. That means that you won't be able to log in to those accounts, even if you know the estate owner's login and passwords, until there is a transfer of ownership of those accounts. What's more important is knowing that they exist.