California Code, Unemployment Insurance Code - UIC § 1117

If any employer fails to file the annual reconciliation return described in subdivision (e) of Section 1088 or subdivision (j) of Section 13021 on or before 30 days after notice has been given to the employer of his or her failure to file, unless the failure is due to good cause, the employer, in addition to any other penalties imposed by this code, shall pay a penalty of one thousand dollars ($1,000), or 5 percent of the employer and worker contributions required to be reconciled by subdivision (e) of Section 1088, whichever is less.