Q: What happens if I forgot to declare over $10k cash at customs? Is there a chance to still do it without repercussions?

A: If you failed to declare over $10,000 in cash or monetary instruments when entering the US through customs, it is best to consult with a legal professional about the options. Technically you should have completed a FinCEN 105 Report of International Transportation of Currency or Monetary Instruments at the time. Some things to keep in mind:

- While not properly declaring is a legal violation that can incur civil penalties and even potential criminal charges in some cases, voluntarily disclosing now can mitigate penalties substantially if Customs believes the violation was through negligence rather incompetence or illegal intent.

- You may consider filing a late corrected FinCEN 105 form along with a written explanation with Customs & Border Protection to properly declare, albeit late. This may incur much smaller violations than if caught, but does still risk penalties.

- If the funds have already been deposited into a U.S. bank, providing supporting bank documentation showing the recent deposit trail could aid such a late disclosure to provide transparency.

- An attorney can help negotiate and interact with Customs on your behalf to minimize penalties or demonstrate it was an inadvertent mistake rather than willful deception or laundering.

I would not recommend ignoring the situation as penalties can be quite severe if caught in an audit. Voluntarily trying to remedy apparent good-faith mistakes is looked upon much more favorably, though. Consultation with an attorney knowledgeable in these matters is highly advisable.