Dec 31 for audits. I believe Dec 15-20 none audit based on past Onci filings. Last year was Jan 31. Although with extension 120 days post Oct31 may be granted.

http://www.finra.org/sites/default/files/noti...113017.pdf
https://www.sec.gov/divisions/corpfin/cffinan...manual.pdf
https://www.otcmarkets.com/stock/ONCI/disclosure