It's considered substantially improved when you spend at least as much as the property's initial basis over a 30-month period. The property's initial basis should be determined without regard to land. There is some ambiguity as to when the 30-month period begins, but it's reasonable to take the position the period should begin when physical work commences, as opposed to the date of purchase or when planning work starts.
In general, you must invest at least the same amount as the adjusted basis of the property when acquired. There are other special rules that may apply as to agreggation, etc.
DISCLAIMER:the information found on this website is intended to be general information; it is not legal or financial advice. Specific legal or financial advice can only be given by a licensed professional with full knowledge of all the facts and circumstances of your particular situation. You should seek consultation with legal and financial experts prior to participating in any aspect relating to Opportunity Zones. Posting a question on this website does not create an attorney-client relationship. All questions you post will be available to the public; do not include confidential information in your question.