26 USC 6708 - Failure to maintain lists of advisees with respect to reportable transactions

(a) Imposition of penalty 

(1) In general 
If any person who is required to maintain a list under section 6112 (a) fails to make such list available upon written request to the Secretary in accordance with section 6112 (b) within 20 business days after the date of such request, such person shall pay a penalty of $10,000 for each day of such failure after such 20th day.
(2) Reasonable cause exception 
No penalty shall be imposed by paragraph (1) with respect to the failure on any day if such failure is due to reasonable cause.
(b) Penalty in addition to other penalties 
The penalty imposed by this section shall be in addition to any other penalty provided by law.