Which of the following is NOT a responsibility of the managing partner?

The role of a managing partner typically involves a range of responsibilities aimed at ensuring the smooth operation of the partnership. This includes overseeing daily operations, which entails managing the day-to-day functions of the firm. Making strategic decisions also falls under the purview of a managing partner, as they are often tasked with setting long-term goals and directing the firm's growth strategies.

Defending against lawsuits is a legal responsibility that may arise, especially in a law firm setting, where the managing partner could be involved in managing legal risks and litigation matters concerning the firm.

Mining for investment opportunities, however, is not a standard responsibility of a managing partner. While they may have some involvement in exploring new avenues for the firm's growth, this task is typically more aligned with roles such as a financial officer or a business development director, who specifically focus on identifying and securing investments. Thus, this option does not reflect the core responsibilities that a managing partner would typically undertake, making it the correct choice for what is NOT a responsibility of the managing partner.