Which of these is NOT included in the FCA handbook definitions of market abuse?

Market positioning is not defined as a form of market abuse within the FCA handbook. The FCA specifies particular behaviors that constitute market abuse, including insider dealing, which involves trading based on non-public, price-sensitive information, manipulating transactions, where someone intentionally affects the market price or volume of a security, and unlawful disclosure, which refers to the illegal sharing of information in a way that can influence market prices or trading decisions.

These behaviors are clearly outlined as practices that harm market integrity and investor confidence. Market positioning, however, generally refers more to the strategic placement of trades or investments to achieve certain objectives and does not fall under the legal definitions of harmful market abuse as specified by the FCA. Therefore, it is the correct choice for what is not included in the definitions of market abuse.