Putnam Associates may be shaking up the Vault 50 ranking, but when it comes to its boutique roots, it actually ceded the top spot back to the Insight Sourcing Group, which had held the top spot the two years previous. While ISG Is the undisputed champ, it could face intensified pressure in 2019, with ClearView Healthcare Partners, the Bridgespan Group, and the Ignyte Group all gobbling significant ground in the 2018 ranking.