Professional practices in Texas are in luck: Texas Business Organizations Code §301.011 reads as follows:
EXEMPTION FROM SECURITIES LAWS.
(a) A sale, issuance, or offer for sale of an ownership interest in a professional entity to a person authorized under this title to own an ownership interest in the professional entity is exempt from any state law, other than this code, that regulates the sale, issuance, or offer for sale of securities.
(b) A transaction described by Subsection (a) does not require the approval of or other action by a state official or regulatory agency authorized to regulate the sale, issuance, or offer for sale of securities.
This means that provided the entity complies with the federal securities regulations, then Texas law won't interfere. This can vastly reduce the cost of forming professional entities in Texas.
While Michigan doesn't expressly exempt interests in professional entities, there is an exemption found in MCL 451.2202(1)(n) which should cover almost all professional practices but the largest law firms:
(n) A sale or an offer to sell securities by or on behalf of an issuer, if the transaction is part of a single issue in which all of the following are met:
(i) There are not more than 50 purchasers in this state during any 12 consecutive months, other than those designated in subdivision (m).
(ii) There is no general solicitation or general advertising used in connection with the offer to sell or sale of the securities.
(iii) A commission or other remuneration is not paid or given, directly or indirectly, to a person other than a broker-dealer registered under this act or an agent registered under this act for soliciting a prospective purchaser in this state.
(iv) The issuer reasonably believes that all the purchasers in this state other than those designated in subdivision (m) are purchasing for investment.