Small Doubt in locks

Hi All, When I do an update/insert (In a transaction) on the small table which has indexes it doesn't put locks on index pages, where as if i do the same in the large table it puts lock in the index page.. Why is it so??? Thanks in Advance. Regards Vasanth ******************************************** This electronic mail message is intended solely for the named recipients and may contain confidential and proprietary business information of eFunds Corporation and all its subsidiaries. If you are not a named recipient, please notify the sender immediately. You may not disclose the contents to any other person; use this electronic mail message or its contents for any other purpose; or further store or copy its contents in any medium. ********************************************