* `UBTI`, which refers to "unrelated business taxable income.

Not that donor-advised funds and government grants don't currently have their

own `IncomeType`.  It's possible this might be necessary; the authors aren't

familiar with how to handle those items on the Form 990.  It would be a

relatively simple change to `config-tags.ledger`, though, to support other

income types, or to change it entirely to handle use-cases other than USA

Form 990 filing.

#### TaxImplication Tag

The `TaxImplication:` tag is used for all `Asset:` accounts when the

transaction includes a payment of $10.00 or more leaving the account.  This

tag catalogs any tax implications that might occur on outgoing funds.

The most important USA-related issue tracked by this tag are contractors who

must have annual 1099 and/or W2 issued.  An [`Entity:` tag](entity-tag) should always

go along with a TaxImplication tag.

The possible values for this field are:

* `1099`, indicating the amount paid requires issuance of a USA Federal Form

  1099 for the `Entity` involved.

* `Accountant-Advises-No-1099`, indicating that the circumstances and rules

  seem to indicate a USA Federal Form 1099 should be issued for the `Entity`

  involved, but an outside accountant advised that no 1099 need be issues for

  this `Entity`.

* `Bank-Transfer`, indicating that the amount is a transfer between two

  banking accounts under the control of the NPO itself.

* `Foreign-Individual-Contractor`, indicating that the NPO has established

  that the `Entity` is a contractor residing outside the USA who is not a USA

  citizen and does not for any reason pay taxes in the USA.

* `Foreign-Corporation`, indicating that the NPO has established

  that the `Entity` is a corporation outside the USA.

* `USA-Corporation`, indicating that the NPO has established that the

  `Entity` is an incorporated entity the USA (i.e., "Inc."), and therefore no

  1099 is required.

* `USA-501c3`, indicating that the NPO has established that the `Entity`

  has federal 501(c)(3) status in the USA, and therefore no 1099 is required.

* `Refund`, indicating that the amount is a refund owed to the `Entity` from

  an amount previously paid to the NPO.