SQL Server Agent TSQL Query using sp_OACreate. What NT security does the dbo SQL user have?

I have a TSQL script that calls a COM object from it. The running user (SQL Agent scheduler) runs it with a dbo login from SQL so who's security does it connect to the COM object as? The login process of SQL Agent, the login process of SQL server or something else?

DECLARE @oQBXMLrp int
DECLARE @iHR int
DECLARE @iCnt int
DECLARE @sSource varchar(255)
DECLARE @sDesc varchar(255)
DECLARE @sObjectName varchar(255)

SET @iCnt = 1
SELECT "Current User: " = CURRENT_USER, " Time: " = CONVERT(char(30), CURRENT_TIMESTAMP)
WHILE @iCnt < 6 BEGIN
    SET @sObjectName = CASE @iCnt
        WHEN 1 THEN 'QBXMLRPEQODBCInteractive.RequestProcessor'
        WHEN 2 THEN 'QBXMLRP.RequestProcessor'
        WHEN 3 THEN 'QBXMLRP2EQODBCInteractive.RequestProcessor'
        WHEN 4 THEN 'QBXMLRP2.RequestProcessor'
        ELSE 'Xerces.DOMDocument'
    END
    EXEC @iHR = sp_OACreate @sObjectName, @oQBXMLrp OUT
    IF @iHR <> 0 BEGIN
        EXEC sp_OAGetErrorInfo @oQBXMLrp, @sSource OUT, @sDesc OUT
        SELECT "Object" = @sObjectName, "Function" = 'CreateObject', "HR" = convert(varbinary(4),@iHR), "Source" = @sSource, "Description" = @sDesc
    END
    ELSE BEGIN
        SELECT "Object" = @sObjectName, "Function" = 'CreateObject', "HR" = convert(varbinary(4),0), "Source" = '', "Description" = 'Successfully Created'
    END

    EXEC @iHR = sp_OADestroy @oQBXMLrp
    SET @iCnt = @iCnt + 1
END