EXHIBIT (a)(5)(O)
                                   VERIO INC.

        NOTICE REGARDING TREATMENT OF UNVESTED OPTIONS IN TENDER OFFER
                             UNDER THE VERIO INC.
         1996 STOCK OPTION PLAN, 1997 CALIFORNIA STOCK OPTION PLAN AND
                           1998 STOCK INCENTIVE PLAN
(Applicable to Option Agreements with "single trigger" acceleration of vesting
                   provision, subject to deferral agreement)

1.   NTT Communications Corporation ("NTT Communications") has made a tender
     offer to purchase all outstanding Common Stock of Verio Inc. ("Verio") for
     cash at a price of $60.00 per share (the "Offer"). This Notice explains the
     effects of the Offer on the portion of your outstanding options to purchase
     shares of Common Stock of Verio that previously were granted to you under
     the terms of Verio's 1996 Stock Option Plan, 1997 California Stock Option
     Plan and/or 1998 Stock Incentive Plan (as applicable, collectively and
     individually, the "Plan") and your Option Agreement(s), and that remain
     unvested immediately prior to the completion of the Offer by NTT
     Communications (the "Unvested Options"). Unless otherwise defined herein,
     the terms defined in your Option Agreement(s) and the Plan shall have the
     same defined meanings in this Notice.

2.   Under the original terms of your Option Agreement(s), your Unvested Options
     automatically would have vested immediately upon completion of the Offer.
     Under the terms of the Stock Option Deferral Agreement you entered into
     with Verio at the time the agreement with NTT Communications was signed,
     however, you have elected to defer vesting of a portion of your Unvested
     Options in return for certain consideration, as described in your Stock
     Option Deferral Agreement. Accordingly, a portion of your Unvested Options
     (the "Retention Options") will not vest, but instead will be canceled in
     exchange for the right to receive cash in an amount equal to (A) the
     product of (1) the number of Retention Options and (2) the excess, if any,
     of the $60.00 per share Offer price over the applicable exercise price per
     share for the purchase of Common Stock subject to your Retention Options,
     minus (B) all applicable federal, state and local taxes required to be
     withheld in respect of such payment (the "Option Consideration"). One-half
     of the Option Consideration shall be paid to you thirteen (13) months after
     completion of the Offer, and the other half of the Option Consideration
     shall be paid to you twenty-five (25) months after completion of the Offer
     if, in each case, your Continuous Status as an Employee has not yet
     terminated. If you are terminated by Verio within twenty-five (25) months
     after completion of the Offer without Cause (as defined in your Stock
     Option Deferral Agreement) or voluntarily by you with Good Reason (as
     defined in your Stock Option Deferral Agreement), any unpaid Option
     Consideration shall become immediately payable. The Stock Option Deferral
     Agreement also provides for the payment of certain bonus payments at the
     same time as the Option Consideration payments are made.


3.   Upon completion of the Offer, the Plan will be terminated and you will have
     no further rights to acquire the Verio Common Stock represented by your
     Unvested Options.