<PAGE>
                                                                   Exhibit 10.16

              AMENDED AND RESTATED EXECUTIVE SECURITIES AGREEMENT
              ---------------------------------------------------
                                   (RIEDER)

          THIS AMENDED AND RESTATED EXECUTIVE SECURITIES AGREEMENT (this
"Agreement") is made as of May 26, 1999, by and between CompleTel LLC, a
 ---------
Delaware limited liability company (the "Company"), and Hansjorg Rieder
                                         -------
("Executive").  Capitalized terms used but not otherwise defined herein have the
  ---------
meanings ascribed to such terms in Section 6 hereof.

          Pursuant to the terms of an Executive Securities Agreement dated as of
November 12, 1998, by and between the Executive and the Company (the "Prior
Agreement"), the Executive purchased 286 Common Units of the Company. The
parties hereto now desire to enter into an agreement whereby Executive will
purchase additional Common Units of the Company.  In furtherance thereof, the
parties hereto hereby agree to amend and restate the Prior Agreement as set
forth herein.  All of such Executive Securities are subject to time vesting as
set forth herein.  In addition to time vesting, the portion of such Executive
Securities indicated below are also subject to performance vesting pursuant to
the terms of the Performance Vesting Agreement.  All of the Executive Securities
held by Executive or his transferees are subject to certain restrictions on
transfer and, upon Executive's ceasing to be employed by the Company or its
Subsidiaries, certain repurchase options, each as set forth herein.  In
addition, the Executive Securities are subject to certain voting agreements and
other provisions set forth herein and in the Securityholders Agreement.  The
Company's Subsidiary CompleTel GmbH ("CompleTel") entered into an Employment
                                      ---------
Agreement with Executive as its Managing Director (the "Employment Agreement")
                                                        --------------------
in June 1999.

          NOW, THEREFORE, in consideration of the mutual promises made herein
and other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the parties hereto, intending to be legally bound,
agree as follows:

          1.   Purchase of Executive Securities.
               --------------------------------

          (a)  Prior Purchase and Issuance.   Pursuant to the Prior Agreement,
               ---------------------------
the Executive purchased for an aggregate purchase price of $286, and the Company
issued to Executive, 286 Common Units (of which 200 are not, and 86 are, subject
to performance vesting under the terms of the Performance Vesting Agreement),
each having the rights and preferences set forth with respect thereto in the LLC
Agreement.

          (b)  Purchase and Issuance of Additional Executive Securities.  The
               --------------------------------------------------------
Company agrees to issue and sell to Executive and Executive agrees to purchase
from the Company, upon execution of this Agreement and payment of the purchase
price, an additional 321 Common Units (of which 224.9 shall not, and 96.1 shall,
be subject to performance vesting under the terms of the Performance Vesting
Agreement), each having the rights and preferences set forth with respect
thereto in the LLC Agreement.  The aggregate purchase price for the additional
Common Units is $321, which amount shall be paid to the Company, in U.S.
Dollars, by cashier's or certified check, or by wire transfer.
<PAGE>

          (c)  Representations and Warranties of Executive.  In connection with
               -------------------------------------------
the purchase and issuance of the Executive Securities under the Prior Agreement
and hereunder, Executive represents and warrants to the Company that:

               (i)   The Executive Securities acquired by Executive under the
Prior Agreement and to be acquired by Executive pursuant to this Agreement shall
be acquired for Executive's own account and not with a view to, or intention of,
distribution thereof in violation of the Securities Act or any applicable state
securities laws, and the Executive Securities shall not be disposed of in
contravention of the Securities Act or any applicable state securities laws.

               (ii)  Executive is sophisticated in financial matters and is able
to evaluate the risks and benefits of the investment in the Executive
Securities.

               (iii) Executive is able to bear the economic risk of his
investment in the Executive Securities for an indefinite period of time and is
aware that transfer of the Executive Securities may not be possible because (A)
such transfer is subject to contractual restrictions on transfer set forth
herein, in the Securityholders Agreement, and in the Performance Vesting
Agreement, and (B) the Executive Securities have not been registered under the
Securities Act or any applicable state securities laws and, therefore, cannot be
sold unless subsequently registered under the Securities Act and such applicable
state securities laws or an exemption from such registration is available.

               (iv)  Executive has had an opportunity to ask questions and
receive answers concerning the terms and conditions of the offering of the
Executive Securities issued hereunder and has had full access to such other
information concerning the Company as he has requested.

               (v)   This Agreement, the LLC Agreement, the Securityholders
Agreement, the Registration Agreement, the Performance Vesting Agreement, the
Joinder Agreement, and the other agreements contemplated thereby of even date
therewith constitute the legal, valid and binding obligations of Executive,
enforceable in accordance with their terms, and the execution, delivery and
performance of such agreements by Executive and Executive's employment by the
Company and its Subsidiaries do not and shall not conflict with, violate or
cause a breach of any agreement, contract or instrument to which Executive is a
party or by which he is bound or any judgment, order or decree to which
Executive is subject.

          (d)  Acknowledgment by Executive.  As an inducement to the Company to
               ---------------------------
enter into this Agreement, and as a condition thereto, Executive acknowledges
and agrees that this Agreement and the purchase of the Executive Securities
hereunder are not a condition to his employment by the Company or any Subsidiary
and that none of the execution and delivery of this Agreement, the issuance of
the Executive Securities to Executive, or Executive's status as a holder of
Executive Securities, shall:

               (i)   entitle Executive to remain employed by the Company or its
Subsidiaries or affect the right of the Company or its Subsidiaries to terminate
Executive's employment at any time and for any reason as permitted by the
Employment Agreement; or

                                      -2-
<PAGE>

               (ii)  impose upon the Company any duty or obligation to disclose
to Executive, or create in Executive any right to be advised of, any material
information regarding the Company and its Subsidiaries at any time prior to,
upon or in connection with the repurchase of any Executive Securities upon the
termination of Executive's employment by the Company or its Subsidiaries or as
otherwise provided hereunder.

          2.   Time Vesting of Executive Securities.
               ------------------------------------

          (a)  Time Vesting Schedule.  Except as otherwise provided herein, an
               ---------------------
amount of Un-Time-Vested Securities (as defined below) shall time vest on
December 31, 1998, on each of the first three anniversaries of such date, and on
November 12, 2002, such that the Executive Securities shall be time vested on
each such date in accordance with the following schedule:

-------------------------------------------------------------------------------
                                             Cumulative Percentage of
                                               Executive Securities
                 Date                        Time Vested on Such Date
                 ----                        ------------------------
-------------------------------------------------------------------------------
          December 31, 1998                               4.17%
-------------------------------------------------------------------------------
          December 31, 1999                              29.17%
-------------------------------------------------------------------------------
          December 31, 2000                              54.17%
-------------------------------------------------------------------------------
          December 31, 2001                              79.17%
-------------------------------------------------------------------------------
          November 12, 2002                                100%
-------------------------------------------------------------------------------

Notwithstanding the foregoing sentence, the above time vesting schedule shall
cease and no Un-Time-Vested Securities (as defined below) shall time vest after
the date on which Executive's employment with the Company or its Subsidiaries
terminates voluntarily, involuntarily, with or without cause, for any reason or
for no reason.  Executive Securities which have become time vested pursuant to
this Section 2 are referred to herein as "Time-Vested Securities," and all other
                                          ----------------------
Executive Securities are referred to herein as "Un-Time-Vested Securities."
                                                -------------------------

          (b)  100% Acceleration upon a Qualified Sale of the Company.  All Un-
               ------------------------------------------------------
Time-Vested Securities shall become Time-Vested Securities in connection with
the consummation of a Qualified Sale of the Company, so long as Executive is
employed by the Company or any of its Subsidiaries on the date of such sale.
For purposes hereof, a "Qualified Sale of the Company" means a Sale of the
                        -----------------------------
Company in which the consideration paid in such sale for at least 50% of the
Company's outstanding equity securities or of the Company's consolidated assets
consists of cash and/or publicly traded equity securities (e.g., 66.7% of the
consideration for such Sale of the Company would have to consist of cash and/or
publicly traded equity securities if only 75% of the Company's outstanding
equity securities were sold in such transaction).

          (c)  100% Acceleration upon a Sale of the Company (other than a
               ----------------------------------------------------------
Qualified Sale of the Company) with No Continuing Comparable Time Vesting
-------------------------------------------------------------------------
Arrangement.  In the event of a Sale
-----------

                                      -3-
<PAGE>

of the Company (other than a Qualified Sale of the Company), the above vesting
schedule will not accelerate as a result of such Sale of the Company; provided
                                                                      --------
that if the surviving or acquiring Person(s) in such Sale of the Company fails
or declines either to (i) continue after such Sale of the Company to allow
Executive to hold his Un-Time-Vested Securities subject to the time vesting and
repurchase provisions hereof, or (ii) grant to Executive the number of
securities in the surviving or acquiring Person(s) that Executive would have
received in such Sale of the Company in exchange for Executive's Un-Time-Vested
Securities if such securities had instead been Time-Vested Securities, subject
to ongoing time vesting and repurchase arrangements substantially comparable to
those set forth herein (as such comparability is determined in good faith by the
Board), then all Un-Time-Vested Securities shall become Time-Vested Securities
in connection with the consummation of such Sale of the Company, so long as
Executive is employed by the Company or any of its Subsidiaries on the date of
such sale.

          (d)  One-Year Acceleration upon a Qualified Public Offering.  Upon the
               ------------------------------------------------------
consummation of a Qualified Public Offering, and so long as Executive is
employed by the Company or any of its Subsidiaries on the closing date of such
offering, there will time vest the amount of Un-Time-Vested Securities which
were scheduled to time vest within the 365 days following such closing date (and
the remaining Un-Time-Vested Securities, if any, shall continue to time vest in
accordance with paragraph (a) above, such that the time vesting schedule set
forth in paragraph (a) above shall have been effectively accelerated by one
year).

          (e)  Time Vesting and Performance Vesting.
               ------------------------------------

               (i)   Independence of Time and Performance Vesting.  The Company
                     --------------------------------------------
and Executive acknowledge that the Executive Securities constituting Performance
Vesting Securities are subject, in addition to time vesting under this Section
2, to performance vesting as set forth in the Performance Vesting Agreement.
The time vesting provisions of this Section 2 operate independently of the
performance vesting provisions under the Performance Vesting Agreement. As such,
(A) the terms "Time-Vested Securities" and "Un-Time-Vested Securities" as used
herein refer only to whether particular Executive Securities have time vested in
accordance with the terms of this Section 2 and do not indicate whether such
Executive Securities that constitute Performance Vesting Securities have or have
not also performance vested under the Performance Vesting Agreement, and (B) the
terms "Performance-Vested Securities" and "Un-Performance-Vested Securities"
(each defined below) as used herein refer only to whether particular Performance
Vesting Securities have performance vested in accordance with the terms of the
Performance Vesting Agreement and do not indicate whether such Performance
Vesting Securities have or have not also time vested under this Section 2.

               (ii)  Application of Time Vesting.  Whenever Un-Time-Vested
                     ---------------------------
Securities time vest pursuant to the terms of this Section 2, the Un-Time-Vested
Securities that are not Performance Vesting Securities, on the one hand, and the
Un-Time-Vested Securities that are Performance Vesting Securities, on the other
hand, will each time vest on a pro rata basis based on the number of each such
type of securities then outstanding.  Of such Un-Time-Vested Securities
constituting Performance Vesting Securities which are to vest, the Un-Time-
Vested Securities that

                                      -4-
<PAGE>

are Performance-Vested Securities shall be time vested prior to any Un-Time-
Vested Securities that are Un-Performance-Vested Securities being time vested.

               (iii) Application of Performance Vesting.  Whenever Un-
                     ----------------------------------
Performance-Vested Securities performance vest pursuant to the terms of the
Performance Vesting Agreement, the Un-Performance-Vested Securities that are
Time-Vested Securities shall be performance vested prior to any Un-Performance-
Vested Securities that are Un-Time-Vested Securities being performance vested.

          3.   Repurchase Options
               ------------------

          (a)  Repurchase Option Upon Cessation of Employment.  If Executive
               ----------------------------------------------
ceases voluntarily or involuntarily, with or without cause, to be employed by
the Company or its Subsidiaries for any reason or for no reason (such cessation
of employment, a "Repurchase Event"), the Company (by action of the Board) may
                  ----------------
elect to purchase all or any portion of the Executive Securities then in
existence (whether held by Executive or one or more of Executive's transferees)
by delivering a Repurchase Notice to the holder or holders of the Executive
Securities at any time within 30 days after the Repurchase Event.

          (b)  Assignment of Company's Repurchase Rights.  Upon any Repurchase
               -----------------------------------------
Event, the Company (by action of the Board) shall have the right to assign all
or any portion of its repurchase rights hereunder to one or more management or
other key employees (each a "Key Employee") of the Company or any of its
                             ------------
Subsidiaries; provided that the Company may not assign its rights under Section
              --------
3(e) below to pay all or part of the Repurchase Price (as defined below) for
Executive Securities repurchased hereunder by (i) offsetting debts owed by
Executive to the Company or (ii) issuing Class A Senior Units or a promissory
note.  If the Company assigns any of its repurchase rights to such a Key
Employee, and such Key Employee fails to exercise such assigned repurchase
rights, the Company shall once again have the right to exercise (or assign) such
rights.

          (c)  Repurchase Price.  The repurchase price (the "Repurchase Price")
               ----------------                              ----------------
for any Time-Vested Securities to be repurchased hereunder shall be the Fair
Market Value of such securities on the date of the Repurchase Event giving rise
to such repurchase.  The Repurchase Price of any Un-Time-Vested Securities to be
repurchased hereunder shall be the Original Cost of such securities (with
securities having a lower Original Cost being subject to repurchase prior to
securities with a higher Original Cost).

          (d)  Repurchase Notice.  Each "Repurchase Notice" delivered hereunder
               -----------------         -----------------
shall set forth the amount, type, and class of Executive Securities (including,
if applicable, the amount of Un-Time-Vested Securities and/or Time-Vested
Securities) to be acquired from each such holder and the aggregate consideration
to be paid for such Executive Securities, and the time and place for closing of
the repurchase (which date shall not be more than 60 days nor less than 10 days
after the delivery of such Repurchase Notice).  The Executive Securities to be
repurchased pursuant to any Repurchase Notice shall first be satisfied to the
extent possible from the Executive Securities held by Executive at the time of
delivery of such Repurchase Notice.  If the amount of Executive Securities then
held by Executive is less than the total amount of Executive Securities that
have been

                                      -5-
<PAGE>

elected to be purchased pursuant to such Repurchase Notice, the electing party
or parties shall purchase the remaining securities elected to be purchased from
the other holder(s) of Executive Securities, pro rata according to the amount of
Executive Securities held of record by each such other holder at the time of
delivery of such Repurchase Notice. The amount of Un-Time-Vested Securities and
Time-Vested Securities repurchased hereunder shall be deemed to be allocated
among Executive and the other holders of repurchased Executive Securities (if
any) pro rata according to the amount of Executive Securities to be purchased
from such persons.

          (e)  Closing of Each Repurchase.  The closing of any repurchase of
               --------------------------
Executive Securities hereunder shall occur at the date and time specified in the
applicable Repurchase Notice with respect to such repurchase.  At each such
closing, the holders of Executive Securities shall deliver all certificates (if
any exist) evidencing the Executive Securities to be repurchased at such closing
to the purchaser or purchasers thereof, and such purchaser or purchasers shall
pay for the Executive Securities to be purchased at such closing by delivery of
a check or wire transfer of immediately available funds in the aggregate amount
of the Repurchase Price for such Executive Securities; provided that if the
                                                       --------
Company is to purchase any Executive Securities from Executive at such closing,
the Company may elect (by action of the Board) to pay all or any portion of the
Repurchase Price for such Executive Securities by setting off against such
Repurchase Price any bona fide debts owed (regardless of whether then due and
payable) by Executive to the Company or any of its Subsidiaries; and provided
                                                                 ------------
further that if the Company is to purchase any Executive Securities at such
-------
closing, the Company may elect (by action of the Board) to pay all or any
portion of the Repurchase Price for such Executive Securities as follows:

               (i)  in accordance with the LLC Agreement, by issuing in exchange
for such Executive Securities an equal number of Class A Senior Units, and each
such Class A Senior Unit issued in connection with such repurchase shall be
deemed as of the date of such repurchase to have capital contributions to the
Company made with respect to such Class A Senior Unit equal to the Repurchase
Price for the Executive Securities in exchange for which such Class A Senior
Unit was issued; or

               (ii) if the Company has prior to the date of such repurchase
converted into a corporation or other corporate form, in the form of a
promissory note, which promissory note shall be subordinated to all of the
Company's senior debt obligations either then or thereafter incurred, shall earn
simple annual interest at a rate of 8% per annum, shall have all principal and
accrued interest due and payable upon maturity, and shall mature upon the
earliest to occur of the Company's initial Public Offering (if such initial
Public Offering has not occurred prior to the issuance of such promissory note),
a Sale of the Company, or the fourth anniversary of the issuance of such
promissory note.

     The purchasers of Executive Securities hereunder shall be entitled to
receive customary representations and warranties from the sellers, including
representations and warranties regarding good title to such securities, free and
clear of any liens or encumbrances.

          (f)  Restrictions.  Notwithstanding anything to the contrary contained
               ------------
in this Agreement, all repurchases of Executive Securities by the Company shall
be subject to applicable

                                      -6-
<PAGE>

restrictions contained in the Delaware General Corporation Law, the Delaware
Limited Liability Company Act and in the Company's and its Subsidiaries' debt
and equity financing agreements. If any such restrictions prohibit the
repurchase of Executive Securities hereunder which the Company is otherwise
entitled to make, the time periods provided in this paragraph 3 shall be
suspended, and the Company may make such repurchases as soon as it is permitted
to do so under such restrictions, unless by such time such repurchase option has
terminated pursuant to paragraph (g) below.

          (g)  Termination of Repurchase Options.  The repurchase provisions
               ---------------------------------
under this paragraph 3 (and the rights and obligations created thereby) shall
cease to apply to all Time-Vested Securities upon the consummation of a
Qualified Sale of the Company or a Qualified Public Offering (it being
understood that (i) such provisions, rights, and obligations shall continue to
apply to all Un-Time-Vested Securities until such time as they become Time-
Vested Securities in accordance with the terms hereof, and (ii) the forfeiture
provisions of the Performance Vesting Agreement shall continue to apply to all
Un-Performance-Vested Securities until such time as they become Performance-
Vested Securities in accordance with the terms of the Performance Vesting
Agreement).

          4.   Restrictions on Transfer.
               ------------------------

          (a)  Opinion of Valid Transfer.  In addition to any other restrictions
               -------------------------
on transfer imposed by this Agreement, the Securityholders Agreement, the
Performance Vesting Agreement, or the LLC Agreement, no holder of Executive
Securities may sell, transfer or dispose of any Executive Securities (except
pursuant to an effective registration statement under the Securities Act)
without first delivering to the Company an opinion of counsel (reasonably
acceptable in form and substance to the Company) that neither registration nor
qualification under the Securities Act or applicable state securities laws is
required in connection with such transfer.

          (b)  Restrictive Legend.  The certificates representing Executive
               ------------------
Securities issued hereunder shall bear a legend in substantially the following
form:

     "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
     REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"),
     OR THE SECURITIES LAWS OF ANY STATE, AND SUCH SECURITIES MAY NOT BE
     SOLD OR TRANSFERRED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION
     STATEMENT UNDER THE ACT OR AN EXEMPTION FROM REGISTRATION THEREUNDER.

     THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE ALSO SUBJECT TO
     ADDITIONAL RESTRICTIONS ON TRANSFER, VESTING PROVISIONS, AND
     REPURCHASE OPTIONS SET FORTH IN AN EXECUTIVE SECURITIES AGREEMENT
     BETWEEN THE ISSUER OF SUCH SECURITIES (THE "ISSUER") AND THE INITIAL
     HOLDER OF SUCH SECURITIES. A COPY OF SUCH AGREEMENT MAY BE OBTAINED
     BY THE HOLDER HEREOF AT THE ISSUER'S PRINCIPAL PLACE OF BUSINESS
     WITHOUT CHARGE."

                                      -7-
<PAGE>

The legend set forth above shall be removed from the certificates evidencing any
securities which cease to be Executive Securities.

          (c)  Retention of Executive Securities.
               ---------------------------------

               (i)   Executive shall not sell, transfer, assign, pledge or
otherwise dispose of (whether with or without consideration and whether
voluntarily or involuntarily or by operation of law) any interest in any
Executive Securities (a "Transfer"), except (x) with respect to Un-Performance-
                         --------
Vested Securities, pursuant to the repurchase provisions of Section 3 hereof or
the forfeiture provisions of the Performance Vesting Agreement (each, an "Exempt
                                                                          ------
Transfer"), or (y) with respect to all other Executive Securities, pursuant to
--------
(A) the repurchase provisions of Section 3 hereof, (B) the "Participation
Rights" provisions set forth in the Securityholders Agreement, or (C) a Sale of
the Company (each of (A) through (C), an "Exempt Transfer").
                                          ---------------

               (ii)  The restrictions contained in this paragraph (c) shall not
apply with respect to transfers of Executive Securities (other than Un-
Performance-Vested Securities) (A) pursuant to applicable laws of descent and
distribution or (B) among Executive's Family Group; provided that the
                                                    --------
restrictions contained in this paragraph shall continue to be applicable to the
Executive Securities after any such Transfer, the transferees of such Executive
Securities shall have agreed in writing to be bound by the provisions of this
Agreement with respect to the Executive Securities so transferred, and (prior to
the death of Executive) each such transferee of Executive Securities shall have
entered into proxies and other agreements satisfactory to the holders of a
majority of the Purchaser Securities pursuant to which Executive shall have the
sole right to vote such Executive Securities for all purposes (subject to any
applicable voting agreements set forth herein or in the Securityholders
Agreement).  For purposes of this Agreement, "Family Group" means Executive's
                                              ------------
spouse, siblings and descendants (whether natural or adopted) and any of such
descendants' spouses, any trust which at the time of such Transfer and at all
times thereafter is and remains solely for the benefit of Executive and/or
Executive's spouse, siblings, and/or descendants and/or such descendants'
spouses, and any family partnership the partners of which consist solely of
Executive, such spouse, such siblings, such descendants, such descendants'
spouses, and/or such trusts.

               (iii) The restrictions on the transfer of Executive Securities
set forth in this paragraph (c) shall continue with respect to each Executive
Security following any Transfer thereof (other than an Exempt Transfer);
provided that upon the consummation of a Qualified Public Offering, the
--------
restrictions set forth in this paragraph (c) shall thereafter cease to apply to
all Fully Vested Securities, it being understood that such restrictions shall
continue to apply to all other Executive Securities until such time as they
become Fully Vested Securities.

          5.   Confidentiality.
               ---------------

          (a)  Nondisclosure and Nonuse of Confidential Information.  Executive
               ----------------------------------------------------
shall not disclose or use at any time, either during his employment with the
Company or its Subsidiaries or thereafter, any Confidential Information (as
defined below) of which Executive is or becomes aware, whether or not such
information is developed by him, except to the extent that such disclosure or
use

                                      -8-
<PAGE>

is directly related to and required by Executive's performance of duties
assigned to Executive by the Company or its Subsidiaries. Executive shall take
all appropriate steps to safeguard Confidential Information and to protect it
against disclosure, misuse, espionage, loss and theft. As used in this
Agreement, the term "Confidential Information" means information that is not
                     ------------------------
generally known to the public and that is used, developed or obtained by the
Company or its Subsidiaries in connection with their business, including but not
limited to (i) products or services, (ii) fees, costs and pricing structures,
(iii) designs, (iv) analysis, (v) drawings, photographs and reports, (vi)
computer software, including operating systems, applications and program
listings, (vii) flow charts, manuals and documentation, (viii) data bases, (ix)
accounting and business methods, (x) inventions, devices, new developments,
methods and processes, whether patentable or unpatentable and whether or not
reduced to practice, (xi) customer and client information (including customer or
client lists), (xii) copyrightable works, (xiv) all technology and trade
secrets, (xv) business plans and financial models, and (xvi) all similar and
related information in whatever form.  Confidential Information shall not
include any information that has been published in a form generally available to
the public prior to the date Executive proposes to disclose or use such
information.  Information shall not be deemed to have been published merely
because individual portions of the information have been separately published,
but only if all material features constituting such information have been
published in combination.

          (b)  The Company's Ownership of Intellectual Property.
               ------------------------------------------------

               (i)  Acknowledgment of Company Ownership.  If Executive as part
                    -----------------------------------
of his activities on behalf of the Company or its Subsidiaries generates,
authors or contributes to any invention, design, new development, device,
product, method or process (whether or not patentable or reduced to practice or
constituting Confidential Information), any copyrightable work (whether or not
constituting Confidential Information) or any other form of Confidential
Information relating directly or indirectly to the Company's and its
Subsidiaries' business as now or hereafter conducted (collectively,
"Intellectual Property"), Executive acknowledges that such Intellectual Property
 ---------------------
is the exclusive property of the Company and hereby assigns all right, title and
interest in and to such Intellectual Property to the Company. Any copyrightable
work prepared in whole or in part by Executive will be deemed "a work made for
hire" under Section 201(b) of the 1976 Copyright Act, and the Company shall own
all of the rights comprised by the copyright therein. Executive shall promptly
and fully disclose all Intellectual Property to the Company and shall cooperate
with the Company to protect the Company's interests in and rights to such
Intellectual Property (including, without limitation, providing reasonable
assistance in securing patent protection and copyright registrations and
executing all documents as reasonably requested by the Company, whether such
requests occur prior to or after termination of Executive's employment by the
Company).

               (ii) Executive Invention.  Executive understands that paragraph
                    -------------------
(b)(i) of this Section 5 regarding the Company's ownership of Intellectual
Property does not apply to any invention for which no equipment, supplies,
facilities or trade secret information of the Company were used and which was
developed entirely on Executive's own time, unless (i) the invention relates to
the business of the Company or any of its Subsidiaries or to their actual or
demonstrably anticipated research or development or (ii) the invention results
from any work performed by Executive for the Company or any of its Subsidiaries.

                                      -9-
<PAGE>

          (c)  Delivery of Materials upon Termination of Employment.  As
               ----------------------------------------------------
requested by the Company from time to time and upon the termination of
Executive's employment with the Company and its Subsidiaries for any reason,
Executive shall promptly deliver to the Company all copies and embodiments, in
whatever form, of all Confidential Information and Intellectual Property in
Executive's possession or within his control (including, but not limited to,
written records, notes, photographs, manuals, notebooks, documentation, program
listings, flow charts, magnetic media, disks, diskettes, tapes and all other
materials containing or constituting any Confidential Information or
Intellectual Property) irrespective of the location or form of such material
and, if requested by the Company, shall provide the Company with written
confirmation that all such materials have been delivered to the Company.

          6.   Definitions.
               ------------

          "Agreement" has the meaning set forth in the preamble.
           ---------

          "Board" means the board of managers of the Company or, if the Company
           -----
is hereafter converted into a corporation or other entity form, the board of
directors or comparable governing body of the Company.

          "Cause" means (A) any act by Executive, where in respect of such act
           -----
Executive is ultimately convicted or enters a plea of guilty or nolo contendere
to a felony (or crime of similar gravity under the laws of another
jurisdiction), (B) Executive's willful misconduct, gross negligence,
perpetration of or participation in a fraud, in each case where such acts are
materially injurious to the Company or any of its Subsidiaries or any affiliate
thereof, (C) Executive's breach in any material respect of the provisions of
Section 5 (Confidentiality) or (D) Executive's nonperformance  including without
limitation, failure to perform his duties as directed by the Company or failure
to achieve specific performance objectives established by the Company.

          "Class A Senior Units" means the Class A Senior Units of the Company,
           --------------------
having the rights and preferences set forth in the LLC Agreement.

          "Class B Senior Units" means the Class B Senior Units of the Company,
           --------------------
having the rights and preferences set forth in the LLC Agreement.

          "Class C Senior Units" means the Class C Senior Units of the Company,
           --------------------
having the rights and preferences set forth in the LLC Agreement.

          "Common Units" means the Common Units of the Company, having the
           ------------
rights and preferences set forth in the LLC Agreement.

          "Company" has the meaning set forth in the preamble.
           -------

          "Confidential Information" has the meaning set forth in Section 5(a).
           ------------------------

                                      -10-
<PAGE>

          "Disability" means any illness, accident, injury, physical or mental
           ----------
incapacity or other disability, where such condition has rendered, or is
expected to render (as determined in the good faith judgment of the Board),
Executive unable or unfit to perform effectively the duties and obligations of
his employment or to participate effectively and actively in the management of
the Company for a period of at least 90 days.

          "Equity Purchase Agreement" means the Equity Purchase Agreement dated
           -------------------------
May 18, 1998, and amended and restated as of January 28, 1999, by and among the
Company and certain investors, as amended from time to time in accordance with
the terms thereof.

          "Executive" has the meaning set forth in the preamble.
           ---------

          "Executive Securities" means (i) the Common Units issued to Executive
           --------------------
under the Prior Agreement and the Common Units issued to Executive hereunder and
(ii) any securities issued directly or indirectly with respect to any Executive
Securities by way of a stock split, stock dividend, or other division of
securities, or in connection with a combination of securities, recapitalization,
merger, consolidation, or other reorganization, or upon conversion or exercise
of any of the foregoing; provided that Executive Securities shall not include
                         --------
any Senior Units.  As to any particular securities constituting Executive
Securities, such securities shall cease to be Executive Securities when they
have been (a) effectively registered under the Securities Act and disposed of in
accordance with the registration statement covering them, (b) distributed to the
public through a broker, dealer or market maker pursuant to Rule 144 under the
Securities Act (or any similar provision then in force) or (c) repurchased
pursuant to the provisions hereof or forfeited pursuant to the provisions of the
Performance Vesting Agreement.  "Executive Securities" refers only to Executive
Securities under this Agreement and does not in any way refer to any securities
referred to as Executive Securities under any other executive securities
agreement between the Company and a Key Employee of the Company or its
Subsidiaries.

          "Exempt Transfer" has the meaning set forth in Section 4(c)(i).
           ---------------

          "Fair Market Value" as to any Executive Securities on any particular
           -----------------
date, shall mean the fair market value of such securities as of such date, as
determined in good faith by the Board. With respect to any Executive Securities
that are Un-Performance-Vested Securities, the Board shall in determining the
Fair Market Value of such securities reflect (x) the expected market value of
such securities at such future time as such securities are expected to become
performance vested under the terms of the Performance Vesting Agreement,
appropriately discounted to its present value as of the relevant valuation date
based upon the amount of time from the relevant valuation date until the date on
which such Un-Performance-Vested Securities are expected to performance vest (if
at all), and (y) the magnitude of the risk that such securities may never become
performance vested under the terms of the Performance Vesting Agreement.

          "Family Group" has the meaning set forth in Section 4(c)(ii).
           ------------

          "Fully Vested Securities" means Executive Securities which both (i)
           -----------------------
are Time-Vested Securities and (ii) are not Un-Performance-Vested Securities.

                                      -11-
<PAGE>

          "Intellectual Property" has the meaning set forth in Section 5(b)(i).
           ---------------------

          "Joinder Agreement" means the Joinder and Rights Agreement dated May
           -----------------
18, 1998, as amended and restated of even date herewith, by and between the
Company and the Executive, pursuant to which Executive became a party to the LLC
Agreement, the Securityholders Agreement, the Registration Agreement and the
Performance Vesting Agreement as if he were an original signatory to each such
agreement.

          "Key Employee" has the meaning set forth in Section 3(b).
           ------------

          "LLC Agreement" means the limited liability company agreement
           -------------
governing the affairs of the Company, as amended from time to time in accordance
with its terms.

          "Original Cost," as to any particular securities, shall mean the
           -------------
initial price paid to the Company upon issuance of such securities (as such
price is equitably adjusted for any securities splits, securities dividends,
securities combinations, conversions, recapitalizations or reorganizations).

          "Performance-Vested Securities" means Performance Vesting Securities
           -----------------------------
that have performance vested pursuant to the terms of the Performance Vesting
Agreement.

          "Performance Vesting Agreement" means the Performance Vesting
           -----------------------------
Agreement dated May 18, 1998, and amended and restated as of January 28, 1999,
by and among the Company, certain Key Employees (including Executive), and the
Investors party thereto, as amended from time to time in accordance with its
terms.

          "Performance Vesting Securities" means (i) the Common Units specified
           ------------------------------
in the Performance Vesting Agreement as subject to performance vesting
thereunder (regardless of whether such Common Units have or have not performance
vested pursuant to the terms thereof), and (ii) any securities issued directly
or indirectly with respect to any Performance Vesting Securities by way of a
stock split, stock dividend, or other division of securities, or in connection
with a combination of securities, recapitalization, merger, consolidation, or
other reorganization, or upon conversion or exercise of any of the foregoing;
provided that Performance Vesting Securities shall not include any Senior Units.
--------
As to any particular securities constituting Performance Vesting Securities,
such securities shall cease to be Performance Vesting Securities when they have
been (a) effectively registered under the Securities Act and disposed of in
accordance with the registration statement covering them, (b) distributed to the
public through a broker, dealer or market maker pursuant to Rule 144 under the
Securities Act (or any similar provision then in force) or (c) repurchased
pursuant to the provisions hereof or forfeited pursuant to the provisions of the
Performance Vesting Agreement.

          "Person" means an individual, a partnership, a corporation, a limited
           ------
liability company, an association, a joint stock company, a trust, a joint
venture, an unincorporated organization and a governmental entity or any
department, agency or political subdivision thereof.

                                      -12-
<PAGE>

          "Preferred Units" means the Preferred Units of the Company, having the
           ---------------
rights and preferences set forth in the LLC Agreement.

          "Prior Agreement" has the meaning given in the recitals.
           ---------------

          "Public Offering" means any underwritten sale of the company's common
           ---------------
stock pursuant to an effective registration statement under the Securities Act
filed with the Securities and Exchange Commission on Form S-1 (or a successor
form adopted by the Securities and Exchange Commission); provided that the
following shall not be considered a Public Offering: (i) any issuance of common
stock as consideration for a merger or acquisition, and (ii) any issuance of
common stock or rights to acquire common stock to existing securityholders or to
employees of the Company or its Subsidiaries on Form S-4 or Form S-8 (or a
successor form adopted by the Securities and Exchange Commission) or otherwise.

          "Purchaser Securities" means (i) the Preferred Units issued pursuant
           --------------------
to the Equity Purchase Agreement, (ii) any Common Units issued upon conversion
of the Preferred Units referenced in clause (i), and (iii) any securities issued
directly or indirectly with respect to any Purchaser Securities by way of a
stock split, stock dividend, or other division of securities, or in connection
with a combination of securities, recapitalization, merger, consolidation, or
other reorganization, or upon conversion or exercise of any of the foregoing
securities; provided that Purchaser Securities shall not include any Senior
            --------
Units.  As to any particular securities constituting Purchaser Securities, such
securities shall cease to be Purchaser Securities when they have been (a)
effectively registered under the Securities Act and disposed of in accordance
with the registration statement covering them, (b) distributed to the public
through a broker, dealer or market maker pursuant to Rule 144 under the
Securities Act (or any similar provision then in force) or (c) repurchased or
otherwise acquired by the Company or forfeited pursuant to the provisions of the
Performance Vesting Agreement.  Any reference herein to a "majority of the
Purchaser Securities" or the "number of Purchaser Securities" for purposes of
comparison shall refer, with respect to any particular Purchaser Securities, to
the number of Common Units (or equivalent common equity securities of the
Company) then represented by such Purchaser Securities (on a fully diluted, as-
if-converted basis).

          "Qualified Public Offering" means a Public Offering where both
           -------------------------                                ----

          (i)  the proceeds (net of underwriting discounts and commissions)
     received by the Company in exchange for its issuance of shares of common
     stock in such Public Offering equal or exceed $60 million, and
                                                                ---

          (ii) the price per share of common stock paid to the Company in such
     Public Offering equals or exceeds the product of (x) 3.0 times (y) the
                                                              -----
     quotient of (A) the aggregate capital contributions to the Company under
     the Equity Purchase Agreement (including the initial purchase price and all
     subsequent contributions made in respect of the Preferred Units under the
     terms of the Equity Purchase Agreement) made on or prior to the date of
     such Public Offering with respect to all Purchaser Securities then
     outstanding, divided by (B) the number of shares of the Company's common
                  ----------
     stock represented by all Purchaser Securities

                                      -13-
<PAGE>

     (on a fully diluted, as-if-converted basis) outstanding immediately prior
     to the consummation of such Public Offering.

          "Qualified Sale of the Company" has the meaning set forth in Section
           -----------------------------
2(b).

          "Registration Agreement" means the Registration Agreement dated May
           ----------------------
18, 1998, and amended and restated as of January 28, 1999 entered into by and
among the Company and certain of its securityholders, as amended from time to
time in accordance with its terms.

          "Repurchase Event" has the meaning set forth in Section 3(a).
           ----------------

          "Repurchase Notice" has the meaning set forth in Section 3(d).
           -----------------

          "Repurchase Price" has the meaning set forth in Section 3(c).
           ----------------

          "Sale of the Company" means the arm's length sale of the Company to a
           -------------------
third party or group of third parties acting in concert, pursuant to which such
party or parties acquire (i) equity securities of the Company possessing the
voting power under normal circumstances to control the Company, or (ii) all or
substantially all of the Company's assets determined on a consolidated basis (in
either case, whether by merger, consolidation, sale or transfer of the Company's
equity securities, or sale or transfer of the Company's consolidated assets).

          "Securities Act" means the Securities Act of 1933, as amended, or any
           --------------
similar federal law then in force.

          "Securityholders Agreement" means the Securityholders Agreement dated
           -------------------------
May 18, 1998, and amended and restated as of January 28, 1999 entered into by
and among the Company and certain of its securityholders, as amended from time
to time in accordance with its terms.

          "Senior Units" means the Company's Class A Senior Units, Class B
           ------------
Senior Units, and Class C Senior Units.

          "Subsidiary" means, with respect to any Person, any corporation,
           ----------
limited liability company, partnership, association or other business entity of
which (i) if a corporation, a majority of the total voting power of shares of
stock entitled (without regard to the occurrence of any contingency) to vote in
the election of directors, managers or trustees thereof is at the time owned or
controlled, directly or indirectly, by that Person or one or more of the other
Subsidiaries of that Person or a combination thereof, or (ii) if a limited
liability company, partnership, association or other business entity, a majority
of the partnership or other similar ownership interest thereof is at the time
owned or controlled, directly or indirectly, by any Person or one or more
Subsidiaries of that Person or a combination thereof.  For purposes hereof, a
Person or Persons shall be deemed to have a majority ownership interest in a
limited liability company, partnership, association or other business entity if
such Person or Persons shall be allocated a majority of limited liability
company, partnership, association or

                                      -14-
<PAGE>

other business entity gains or losses or shall be or control any managing
director, manager or general partner of such limited liability company,
partnership, association or other business entity. For purposes of this
Agreement, if the context does not otherwise indicate in respect of which Person
the term "Subsidiary" is used, the term "Subsidiary" shall refer to any
          ----------                     ----------
Subsidiary of the Company.

          "Time-Vested Securities" has the meaning set forth in Section 2(a).
           ----------------------

          "Transfer" has the meaning set forth in Section 4(c)(i).
           --------

          "Un-Performance-Vested Securities" means Performance Vesting
           --------------------------------
Securities that have not yet performance vested pursuant to the provisions of
the Performance Vesting Agreement.

          "Un-Time-Vested Securities" has the meaning set forth in Section 2(a).
           -------------------------

          7.   Miscellaneous Provisions.
               ------------------------

          (a)  Transfers in Violation of Agreement.  Any Transfer or attempted
               -----------------------------------
Transfer of any Executive Securities in violation of any provision of this
Agreement shall be void, and the Company shall not record such purported
Transfer on its books or treat any purported transferee of such Executive
Securities as the owner of such securities for any purpose.

          (b)  Severability. Whenever possible, each provision of this Agreement
               ------------
shall be interpreted in such manner as to be effective and valid under
applicable law, but if any provision of this Agreement is held to be invalid,
illegal or unenforceable in any respect under any applicable law or rule in any
jurisdiction, such invalidity, illegality or unenforceability shall not affect
any other provision or any other jurisdiction, but this Agreement shall be
reformed, construed and enforced in such jurisdiction as if such invalid,
illegal or unenforceable provision had never been contained herein.

          (c)  Complete Agreement.  This Agreement, those documents expressly
               ------------------
referred to herein and related documents among the parties of even date herewith
and therewith embody the complete agreement and understanding among the parties
hereto and supersede and preempt any prior understandings, agreements or
representations by or among the parties, written or oral, which may have related
to the subject matter hereof in any way.

          (d)  Counterparts.  This Agreement may be executed in separate
               ------------
counterparts, none of which need contain the signature of more than one party
hereto but each of which shall be deemed to be an original and all of which
taken together shall constitute one and the same agreement.

          (e)  Successors and Assigns. Except as otherwise provided herein, this
               ----------------------
Agreement shall bind the parties hereto and their respective successors and
assigns and shall inure to the benefit of and be enforceable by the parties
hereto and their respective successors and assigns, whether so expressed or not.

          (f)  Choice of Law.  All issues and questions concerning the
               -------------
construction, validity, enforcement and interpretation of this Agreement shall
be governed by, and

                                      -15-
<PAGE>

construed in accordance with, the laws of the State of Delaware without giving
effect to any choice of law or conflict of law statutes, rules, provisions, or
decisional law (whether of the State of Delaware or any other juris diction)
that would cause the application of the laws of any jurisdiction other than the
State of Delaware. In furtherance of the foregoing, the internal law of the
State of Delaware, without giving effect to any choice of law or conflict of law
statutes, rules, provisions, or decisional law (whether of the State of Delaware
or any other jurisdiction), shall control the interpretation and construction of
this Agreement, even though under that jurisdiction's choice of law or conflict
of law analysis, the substantive law of some other jurisdiction would ordinarily
and otherwise apply.

          (g)  Jurisdiction; Service of Process.   Any actions or proceedings,
               --------------------------------
whether at  law or in equity, seeking to enforce or to enjoin the enforcement of
any provision of this Agreement, or based on any right arising out of this
Agreement shall be brought, tried and litigated against any of the parties in
the courts of the State of Colorado, or, if it has or can acquire jurisdiction,
in the United States District Court for the District of Colorado, and each of
the parties hereby consents to the jurisdiction of such courts (and of the
appropriate appellate courts) in any such action or proceeding and waives any
and all possible objections to venue laid therein, including without limitation
forum non conveniens.  Process in any action or proceeding referred to in the
preceding sentence may be served on any party anywhere in the world by prepaid
Federal Express, DHL or other international air courier to the Executive at the
last known address provided to the Company in writing, to the Company at the
address set forth in Section 7(m) herein or such other address provided to
Executive in writing, and to the last known address of all other addressees.

          (h)  Remedies.  Each of the parties to this Agreement (including any
               --------
Key Employee to which the Company assigns any of its repurchase rights under
Section 3 hereof, as third-party beneficiaries) shall be entitled to enforce its
rights under this Agreement specifically, to recover damages and costs
(including reasonable attorney's fees) caused by any breach of any provision of
this Agreement and to exercise all other rights existing in its favor.  The
parties hereto agree and acknowledge that money damages would not be an adequate
remedy for any breach of the provisions of this Agreement and that any party may
in its sole discretion, subject to the limitations set forth in Section 7(g)
hereof, apply to any court of law or equity of competent jurisdiction (without
posting any bond or deposit) for specific performance and/or other injunctive
relief in order to enforce or prevent any violations of the provisions of this
Agreement.

          (i)  Amendment, Modification, or Waiver.  The provisions of  this
               ----------------------------------
Agreement may be amended, modified, or waived only with the prior written
consent of the Company and the Executive.

          (j)  Third-Party Beneficiaries.  The parties hereto acknowledge and
               -------------------------
agree that certain provisions of this Agreement are intended for the benefit of
any Key Employee to which the Company assigns any of its repurchase rights under
Section 3 hereof, that such Persons are third-party beneficiaries of this
Agreement, and that the provisions of this Agreement shall be enforceable by
such Persons as provided herein.

                                      -16-
<PAGE>

          (k)  Business Days.  If any time period for giving notice or taking
               -------------
action hereunder expires on a day which is a Saturday, Sunday or legal holiday
in the State of Colorado, the State of Germany, or the jurisdiction of the
Company's principal office, the time period shall be extended automatically to
the business day immediately following such Saturday, Sunday or holiday.

          (l)  Descriptive Headings; Interpretation; No Strict Construction. The
               ------------------------------------------------------------
descriptive headings of this Agreement are inserted for convenience only and do
not constitute a substantive part of this Agreement.  Whenever required by the
context, any pronoun used in this Agreement shall include the corresponding
masculine, feminine or neuter forms, and the singular forms of nouns, pronouns,
and verbs shall include the plural and vice versa.  Reference to any agreement,
document, or instrument means such agreement, document, or instrument as amended
or otherwise modified from time to time in accordance with the terms thereof,
and if applicable hereof.  The use of the words "include" or "including" in this
Agreement shall be by way of example rather than by limitation.  The use of the
words "or," "either" or "any" shall not be exclusive.  The parties hereto have
participated jointly in the negotiation and drafting of this Agreement.  If an
ambiguity or question of intent or interpretation arises, this Agreement shall
be construed as if drafted jointly by the parties hereto, and no presumption or
burden of proof shall arise favoring or disfavoring any party by virtue of the
authorship of any of the provisions of this Agreement.

          (m)  Notices. Subject to the requirements regarding service of process
               -------
set forth in Section 7(g) above, all notices, demands or other communications to
be given or delivered under or by reason of the provisions of this Agreement
shall be in writing and shall be deemed to have been given when (a) delivered
personally to the recipient, (b) telecopied to the recipient (with hard copy
sent to the recipient by reputable overnight courier service (charges prepaid)
that same day) if telecopied before 5:00 p.m. Chicago, Illinois time on a
business day, and otherwise on the next business day, or (c) one business day
after being sent to the recipient by reputable overnight courier service
(charges prepaid).  Such notices, demands and other communications shall be sent
to the following Persons at the following addresses:

          To the Company:
          ---------------

          6300 South Syracuse Way, Suite 355
          Englewood, CO 80111
          Attention:   Chief Executive Officer
          Telephone:   (303) 741-4788
          Telecopy:    (303) 741-4823


                                      -17-
<PAGE>

          with a copy (which shall not constitute notice) to:
          ---------------------------------------------------

          Kirkland & Ellis
          200 East Randolph Drive
          Chicago, Illinois 60601
          Attention:    Jeffrey Richards, Esq.
          Telephone:    (312) 861-2385
          Telecopy:     (312) 861-2200

          and with a copy (which shall not constitute notice) to:
          -------------------------------------------------------

          Holme Roberts & Owen LLP
          1700 Lincoln Street
          Suite 4100
          Denver, Colorado 80203
          Attention:    W. Dean Salter, Esq.
          Telephone:    (303) 861-7000
          Telecopy:     (303) 866-0200

          To Executive: at the address set forth in the Company's records

or to such other address or to the attention of such other person as the
recipient party has specified by prior written notice to the sending party.

          (n)  Delivery by Facsimile. This Agreement, the agreements referred to
               ---------------------
herein, and each other agreement or instrument entered into in connection
herewith or therewith or contemplated hereby or thereby, and any amendments
hereto or thereto, to the extent signed and delivered by means of a facsimile
machine, shall be treated in all manner and respects as an original agreement or
instrument and shall be considered to have the same binding legal effect as if
it were the original signed version thereof delivered in person.  At the request
of any party hereto or to any such agreement or instrument, each other party
hereto or thereto shall reexecute original forms thereof and deliver them to all
other parties.  No party hereto or to any such agreement or instrument shall
raise the use of a facsimile machine to deliver a signature or the fact that any
signature or agreement or instrument was transmitted or communicated through the
use of a facsimile machine as a defense to the formation or enforceability of a
contract and each such party forever waives any such defense.

                             *    *    *    *    *

                                      -18-
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have executed this Amended and
Restated Executive Securities Agreement on the date first written above.


                                        COMPLETEL LLC


                                        By:       /s/ William H. Pearson
                                             ----------------------------------
                                             William H. Pearson, President



                                        EXECUTIVE


                                             /s/ Hansjorg Rieder
                                        ---------------------------------------
                                        Hansjorg Rieder




(Signature Page for Executive Securities Agreement)