Retrieving search results from private Groups in Office 365 via REST

By default when you run a search REST query against SharePoint Online results from private Office 365 Groups are not included.

By adding &Properties=’EnableDynamicGroups:true’ to the URL, you will also get results from private groups.

If you are running REST POST requests, add the following to your JSON payload (odata=verbose):

'Properties':{  
         'results':[  
            {  
               'Name':'EnableDynamicGroups',
               'Value':{  
                  'BoolVal':true,
                  'QueryPropertyValueTypeIndex':3
               }
            }
         ]
      }

When using CSOM, it seems dynamic groups are included by default.