A defensive lead is a type of strategy used by private equiteers when attempting to get funding for a target company. In PE firms, partners and associates all bring opportunities forward for potential investment. When a private equiteer uses the defensive lead approach (instead of the all-in approach), the individual is fully responsible for selling the merits of the opportunity to the firm's investment committee as well as seeing the deal through closing, operations, and exit.
Divestopedia explains Defensive Lead
The defensive lead approach can be very stressful for private equiteers to deploy, since it forces them to sell their own partners on the deal. Beyond the convincing part, the private equiteer must ensure the deal delivers the expected returns to the general partnership. Emotions can run high, and the opportunity's merits can be distorted. This emotional aspect may result in an investment with returns below the PE firm's expected threshold, particularly if it is being promoted by an influential member of the firm.