If you try to use PowerShell and CSOM to get SharePoint Online Group Owner information, you learn that the returned Microsoft.SharePoint.Client.Group object Owner property will be empty.  I tried to read value of Owner property and got the following.

I found two ways to get over this.  First I used the basic Object.Retreive method and pass an array or string properties.  The output was show as expected.

To see all the properties you can use

$Owner | Select *

$Group = $Web.SiteGroups.GetByName(“Test”)

$Owner = $Group.Owner

$Owner.Retrieve(“Id”,”LoginName”,”Title”,”PrincipalType”,”IsHiddenInUI”)

$Context.ExecuteQuery() $

$Owner | Select *

The output is exactly as I expected

The second method would be to use Lambda expressions.  PowerShell does not support lambda expressions like C# (object, a => a.XYZ) so I did some research and found a post from PowerShell Guru Garry Lapointe here.  It has a PowerShell script which enables you to call any property of the main object directly. 

https://gist.github.com/glapointe/cc75574a1d4a225f401b#file-load-csomproperties-ps1

$Group = $Web.SiteGroups.GetByName(“Test”)
$Owner = $Group.Owner
Load-CSOMProperties -object $Group.Owner -propertyNames @(“ID”,”LoginName”,”Title”,”PrincipalType”,”IsHiddenInUI”)
$Context.ExecuteQuery()
$Owner | Select *

Output is exactly the same but lot cleaner script as I don’t have to work with Retrieve method.