There is no maximum, assuming you can support your data.
But see this:
<a rel="nofollow" target="_blank" href="https://www.irs.gov/newsroom/business-or-hobby-answer-has-implications-for-deductions">https://www.irs.gov/newsroom/business-or-hobby-answer-has-implications-for-deductions</a>
Also keep in mind that certain business expenses must be amortized, not deducted.
If you checked Box 32b on Schedule C, you must attach Form 6198. Your loss may be limited.
<a rel="nofollow" target="_blank" href="https://www.irs.gov/pub/irs-pdf/f1040sc.pdf">https://www.irs.gov/pub/irs-pdf/f1040sc.pdf</a>
Define "at risk" the entire investment is in hard assets. Ie vehicle, equipment ect . My wife's food truck business which has not begun a serving phase. In reading the rules in the IRS handbook it sounds like all of this investment is at risk. Does that sound correct? Thank you
Those are start up expenses. They cannot be deducted until she is actually open for business.