Texas regulates this more precisely than any other state. Tex. Prop. Code §5.086 requires anyone assigning an interest in a contract to purchase real property to tell a potential buyer, before contracting, that only a contract interest is being assigned and that the assignor holds no legal title. Section 5.0205 demands that disclosure in writing to both the buyer and the property owner. Miss the owner side and the safe harbor at Occ. Code §1101.0045 stops protecting you, which turns the deal into unlicensed brokerage.
Illinois takes the counting approach. The Real Estate License Act of 2000, at 225 ILCS 454/1-10 as amended by Public Act 101-0357, folds anyone engaged in a pattern of business of dealing in assignable contracts or equitable interests into the broker definition, and fixes that pattern at more than one transaction per twelve month period. A second unlicensed assignment inside twelve months is unlicensed brokerage in Illinois. Unlicensed practice is a Class A misdemeanor under 225 ILCS 454/20-22.
California has no wholesaling statute, so exposure runs through Bus. and Prof. Code §10130, which reaches anyone soliciting buyers for real property for another for compensation. Assignability itself is comfortable ground: Civ. Code §1458 makes contract rights transferable, while §1457 confirms that the burden of an obligation moves only with the consent of the party entitled to its benefit.
Florida treats unlicensed brokerage under Fla. Stat. §475.42(1)(a) as a third degree felony. The practical trap is form-based: the widely used Florida Realtors and Florida Bar residential contract is not assignable unless the parties affirmatively elect assignability in the designated paragraph.
New York adds a tax dimension the others do not. Tax Law §1401 expressly addresses the assignment of a contract to purchase real property and excludes the underlying purchase price from consideration, which leaves the assignment fee itself as the measure. Combined with attorney-conducted closings, New York deals need counsel earlier than most markets.
Oklahoma and South Carolina sit at the restrictive end. Oklahoma's Predatory Real Estate Wholesaler Prohibition Act, tightened by SB 1075, requires a license for public marketing of an equitable interest and captures double closings in the definition of wholesaling. South Carolina's H.4754 treats marketing another person's property for compensation as brokerage.