Although the essential role of affect transfer has been evidenced in the brand extension literature, scant research has focused on affect transfer when a firm attempts to add sub-brands into its brand portfolio. We conducted a series of four experiments to demonstrate that affect associated with a family brand does in fact transfer to its sub-brand, and the effect is more pronounced for a sub-brand that is closer to (vs distant from) its family brand. Further, the transfer of affect is contingent upon consideration set size and brand loyalty. While affect transfer is observed when consideration set is small, this effect dissipates when consideration set expands; such moderation effect further interacts with consumers’ loyalty to a family brand and a competing brand. Our findings caution brand managers to take into account consumers’ consideration set size and brand loyalty when managing their brand portfolios.