OBSERVATION: You can see the evolution of law here. A non-tax specialist would anticipate that an activity is exempt if the exempt activity is 51% or more of all activities. The flip side is that a non-exempt activity should be as much as 49%.
The IRS however states that a non-exempt activity cannot be “more than an insubstantial part” of all activities.
Does “insubstantial” mean as much as 49%?
If not, then the IRS is changing definitions all over the place.