EXHIBIT 99.6
GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
NUMBER ON SUBSTITUTE FORM W-9
GUIDELINES FOR DETERMINING THE PROPER IDENTIFICATION NUMBER TO GIVE THE
PAYER. -- Social Security numbers have nine digits separated by two hyphens:
i.e. 000-00-0000. Employer identification numbers have nine digits separated by
only one hyphen: i.e. 00-0000000. The table below will help determine the number
to give the payer.
<Table>
<Caption>
- ---------------------------------------------------------------
GIVE THE SOCIAL
SECURITY NUMBER
FOR THIS TYPE OF ACCOUNT: OF --
- ---------------------------------------------------------------
1. An individual's account The individual
2. Two or more individuals The actual owner of the
(joint account) account or, if combined
funds, any one of the
individuals(1)
3. Husband and wife (joint The actual owner of the
account) account or, if joint funds,
either person(1)
4. Custodian account of a minor The minor(2)
(Uniform Gift to Minors Act)
5. Adult and minor (joint The adult or, if the minor
account) is the only contributor, the
minor(1)
6. Account in the name of The ward, minor or
guardian or committee for a incompetent person(3)
designated ward, minor or
incompetent person
7 a. The usual revocable The grantor-trustee(1)
savings trust account
(grantor is also trustee)
b. So-called trust account The actual owner(1)
that is not a legal or valid
trust under state law
8. Sold proprietorship or The Owner(4)
single owner LLC account
- ---------------------------------------------------------------
</Table>
<Table>
<Caption>
-------------------------------------------------------------------------------
GIVE THE EMPLOYER
IDENTIFICATION NUMBER
FOR THIS TYPE OF ACCOUNT: OF --
-------------------------------------------------------------------------------
9. A valid trust, estate or pension The legal entity (Do not furnish
trust the identifying number of the
personal representative or trustee
unless the legal entity itself is
not designated in the account
title.)(5)
10. Corporate account or LLC electing The corporation
corporate status
11. Religious, charitable, or The organization
educational organization account
12. Partnership or multi-member LLC The partnership
account held in the name of the
business
13. Association, club or other tax- The organization
exempt organization
14. A broker or registered nominee The broker or nominee
15. Account with the Department of The public entity
Agriculture in the name of a
public entity (such as a state or
local government, school district,
or prison) that receives
agricultural program payments
- ---------------------------------------------------------------------------------
</Table>
(1) List first and circle the name of the person whose number you furnish.
(2) Circle the minor's name and furnish the minor's social security number.
(3) Circle the ward's, minor's or incompetent person's name and furnish such
person's social security number.
(4) Show the name of the owner. You may use either your social security number
or employer identification number (if you have one).
(5) List first and circle the name of the legal trust, estate or pension trust.
NOTE: If no name is circled the there is more than one name, the number will be
considered to be that of the first name listed.