From Les Sparks:
I do not know that there is any specific “trigger” on whether of not to disclose. There are very specific requirements for recording. Those are listed below:

.05 The second type consists of those events that provide evidence with respect to conditions that did not exist at the date of the balance sheet being reported on but arose subsequent to that date. These events should not result in adjustment of the financial statements.1 Some of these events, however, may be of such a nature that disclosure of them is required to keep the financial statements from being misleading. Occasionally such an event may be so significant that disclosure can best be made by supplementing the historical financial statements with pro forma financial data giving effect to the event as if it had occurred on the date of the balance sheet. It may be desirable to present pro forma statements, usually a balance sheet only, in columnar form on the face of the historical statements.

.06 Examples of events of the second type that require disclosure to the financial statements (but should not result in adjustment) are:
a. Sale of a bond or capital stock issue.
b. Purchase of a business.
c. Settlement of litigation when the event giving rise to the claim took place subsequent to the balance-sheet date.
d. Loss of plant or inventories as a result of fire or flood.
e. Losses on receivables resulting from conditions (such as a customer’s major casualty) arising subsequent to the balance-sheet date.

Certainly, this is a matter of judgment. However, I can see no reason why I would not disclose it. In fact, I would say required to disclose it.

Les