The stories generated on Facebook users’ news feeds when offers are claimed, and the tendency by users on the social network to share offers make them far more effective than sponsored stories in expanding brands’ reach and virality, according to a recent study by social marketing solutions provider SocialCode.

SocialCode analyzed 122 sponsored page posts (11 offers, 93 photos, and 18 videos) from six of its clients, which generated more than 1.7 billion impressions, and it factored in one month’s worth of insights from those clients.

While engagement rates for offers were lower than those for other sponsored page posts, SocialCode said engagement with offers was far more valuable for brands than, say, likes and comments on photo posts.