Is there any upper limit on the number of customer groups in Magento CE?
99999, if we follow the maximum index in the db. A large amount can influence performances as customer pages are most of the time not cached but else, I do not see any problem to set that amount.
Here is the creation script of the table. The customer_group_id is a smallint with a length of 5 so the maximum index is 99999.
CREATE TABLE IF NOT EXISTS `customer_group` ( `customer_group_id` smallint(5) unsigned NOT NULL COMMENT 'Customer Group Id', `customer_group_code` varchar(32) NOT NULL COMMENT 'Customer Group Code', `tax_class_id` int(10) unsigned NOT NULL DEFAULT '0' COMMENT 'Tax Class Id' ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='Customer Group' AUTO_INCREMENT=4 ; ALTER TABLE `customer_group` ADD PRIMARY KEY (`customer_group_id`); ALTER TABLE `customer_group` MODIFY `customer_group_id` smallint(5) unsigned NOT NULL AUTO_INCREMENT COMMENT 'Customer Group Id',AUTO_INCREMENT=4;