In the multi-armed bandit literature, the multi-bandit best-arm identification problem consists of determining each best arm in a number of disjoint groups of arms, with as few total arm pulls as possible. In this paper, we introduce a variant of the multi-bandit problem with overlapping groups, and present two algorithms for this problem based on successive elimination and lower/upper confidence bounds (LUCB). We bound the number of total arm pulls required for high-probability best-arm identification in every group, and we complement these bounds with a near-matching algorithm-independent lower bound. In addition, we show that a specific choice of the groups recovers the top-k ranking problem. I. INTRODUCTION The multi-armed bandit (MAB) problem [1] provides a versatile framework for sequentially searching for high-reward actions, with applications including clinical trials [2], online advertising [3], adaptive routing [4], and portfolio design [5]. A variation of the MAB problem known as multi-bandit best-arm identification consists of finding the best arm in each of a number of separate groups of arms, while pulling the minimal total number of arms possible [6]. As a motivating example, consider a scenario where each arm corresponds to a product, and pulling an arm corresponds to testing how much it is liked by some user(s). Then the multi-bandit problem corresponds to searching for the top products among multiple separate types (e.g., TV, phone, music player, etc.). Consider a variation of this example in which we not only want to find the top product of each type, but also the top products among several overlapping categories, e.g., top product under $100, top product from each brand name, top newly-released product, and so on. This motivates the overlapping multi-bandit best arm identification problem (or overlapping multi-bandit problem for short), which we introduce and study in this paper. In a nutshell, we seek to find each best arm in a number of overlapping groups using as few total arm pulls as possible; see Section II for a formal description. Beyond the preceding example, the consideration of overlapping groups is of considerable interest when arms correspond to users, since categories such as gender, age, marital status, etc. invariably exhibit overlap.