When Facebook reports third-quarter earnings later this month, the results are expected to show that the summer advertiser boycott had little discernible impact on its advertising revenues. But what was likely crumbs falling from the table for Facebook appears to have been a feast for its smaller rivals, Snap and Pinterest.

Snap in particular appears to have reaped the biggest windfall. Advertiser spending on the Snapchat app more than doubled from July to September compared to the same period last year, according to data from ad tech firm Mediaocean. Some advertisers that paused their Facebook spending during the boycott shifted their entire monthly budget to Snapchat, said Melanie Rhoads, group director of strategic accounts at media-buying agency NXD Social. She declined to identify specific advertisers.