<p>Brand alliances—or co-brands, which feature two brands in one offering—have grown as a strategic marketing tool. Yet, an unexamined aspect of this strategy is how many unique alliances a brand should be engaging in at one time. Is it better to have one exclusive partner, or have multiple offerings with different partners? Additionally, does this differ based on the type of alliance, namely, ingredient brand alliances (a fundamental change to the product) or symbolic brand alliances (often mere packaging changes)? Using large-scale panel purchase data covering 22&#xa0;years, we find that engaging in multiple brand alliances yielded higher average aggregate market share for the brand, but single brand alliances had better average market share. Ingredient alliances also showed greater market share and positively moderated the number of alliances on total market share. Yet, there is a limiting return to alliance engagement, as too many alliances marginally lower total market share. The implication is if brands wish to grab as much market share as possible, brands should offer multiple products using alliances, but if brands seek efficiency, a single brand alliance should be pursued.</p>