What is the term for spying conducted for personal monetary benefits?

The term that best describes spying conducted for personal monetary benefits is "financial gain espionage." This phrase specifically highlights the motivation behind the espionage activities, which is the pursuit of personal financial rewards. This specification sets it apart from broader terms used in intelligence work.

Corporate espionage, while related, generally refers to spying conducted for the benefit of a corporation rather than for individual monetary gain. Intelligence gathering is a more neutral term that can include various types of information collection and does not inherently imply a financial motive. Data theft, on the other hand, focuses specifically on the unauthorized access and removal of data, which may or may not be for personal financial gain. In contrast, financial gain espionage clearly defines the intent behind the spying as a drive for personal profit, making it the most accurate choice in this context.