this is from IRC section 183 which deals with hobby losses
(d)Presumption
If the gross income derived from an activity for 3 or more of the taxable years in the period of 5 consecutive taxable years which ends with the taxable year exceeds the deductions attributable to such activity (determined without regard to whether or not such activity is engaged in for profit), then, unless the Secretary establishes to the contrary, such activity shall be presumed for purposes of this chapter for such taxable year to be an activity engaged in for profit.
so if let's say you don't meet the 3 out of 5 year profit rule. how to show the IRS it's an activity for profit.
see this IRS webpage for what the IRS takes into consideration. keep good documentation of what you are doing to meet these criteria. a written business plan is useful
https://www.irs.gov/newsroom/heres-how-to-tell-the-difference-between-a-hobby-and-a-business-for-tax...
