I own a LLC that's not very active. Is there a situation when the IRS flags this? Previous filings: 14 Small profit 15 Small loss 16/17 $0/not filed 18 Small loss

There is a safe harbor that allows a presumption that you are engaged in for profit if in 3 of 5 consecutive years the activity is profitable.

 

See https://www.irs.gov/pub/irs-utl/irc183activitiesnotengagedinforprofit.pdf

 

However, the IRS uses nine factors to distinguish between a hobby or business activity.

 

See https://www.irs.gov/faqs/small-business-self-employed-other-business/income-expenses/income-expenses