"THE SECURITIES REPRESENTED BY THIS OPTION AGREEMENT HAVE NOT BEEN REGISTERED
UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY
STATE AND MAY NOT BE SOLD OR OTHERWISE DISPOSED OF EXCEPT PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT UNDER SUCH ACT AND APPLICABLE STATE SECURITIES
LAWS OR PURSUANT TO AN APPLICABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS
OF SUCH ACT AND SUCH LAWS."

                                OPTION AGREEMENT


         THIS OPTION AGREEMENT (the "Agreement") is made as of April 11, 2000,
by and between US LEC CORP., a Delaware corporation (the "Company"), and the
Persons whose names are set forth on Schedule 1 attached hereto (individually, a
"Purchaser" and collectively, the "Purchasers")

                              W I T N E S S E T H:

         WHEREAS, the Company and the Purchasers are parties to a Preferred
Stock Purchase Agreement dated as of April 11, 2000 (the "Purchase Agreement");

         WHEREAS, pursuant to the terms and conditions of the Purchase
Agreement, the Company has agreed to sell, and the Purchasers have agreed to
purchase, an aggregate of 200,000 shares of the Company's Series A Convertible
Preferred Stock which are convertible into shares of the Company's Class A
Common Stock, par value $.01 per share (the "Common Stock"); and

         WHEREAS, the parties hereto now wish to provide for an option whereby
the Purchasers shall have the right to purchase an aggregate of up to 100,000
shares of the Preferred Stock (as defined in Article I below), subject to the
terms and conditions contained herein;

         NOW, THEREFORE, in consideration of the foregoing and the
representations, covenants and agreements contained herein, and certain other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

<PAGE>
                                    ARTICLE I

                                   DEFINITIONS

         Unless otherwise defined herein, capitalized terms used herein shall
have the meaning given such terms below. Capitalized terms used herein and not
defined shall have the meanings set forth in the Purchase Agreement.

         "ACQUISITION" means (i) the Company has consolidated with, or merged
with or into, any other Person and, in connection with any such consolidation or
merger, the holders of the Company's Common Stock and Class B Common Stock
outstanding immediately prior to such transaction do not own, in the aggregate,
at least 50% of the outstanding stock of the surviving entity in such
transaction, or (ii) any Person has made a tender offer or exchange offer to
acquire all of the Company's outstanding Common Stock and Class B Common Stock
(each such offer, a "Tender Offer"), and, upon the consummation of the Tender
Offer, the holders of the Company's Common Stock and Class B Common Stock
outstanding immediately prior thereto do not own, in the aggregate at least 50%
of the outstanding stock of the Person that made the Tender Offer.

         "ACQUISITION PROPOSAL" means a written proposal submitted to the
Chairman, Chief Executive Officer, President or Chief Financial Officer of the
Company (each, an "Executive Officer") that (i) proposes a transaction that
would, if consummated, result in an Acquisition, (ii) values the Company at not
less than 120% of the Company's market capitalization at the time it is
submitted and (iii) the Executive Officers, after consultation among themselves,
have determined the proposal is a bona fide one that the Company should or is
required to discuss with the Person that submitted it or is then discussing the
proposal with the Person that submitted it.

         "CLOSING" has the meaning assigned thereto in Section 2.2.

         "CLOSING DATE" has the meaning assigned thereto in Section 2.2.

         "COMPANY INDEMNIFIED PARTY" has the meaning assigned thereto in Section
8.1.

         "EXERCISE NOTICE" has the meaning assigned thereto in Section 2.1(a).

         "EXERCISE PERIOD" has the meaning assigned thereto in Section 2.1(c).

         "INVESTOR AGENTS" has the meaning assigned to such term in the
Corporate Governance Agreement.

         "MARKET PRICE" of any security means the average (weighted by daily
trading volume) of the closing prices of such security's sales on all securities
exchanges on which such security may be listed at the time, or, if there has
been no sales on any such exchange on any day, or, if on any day such security
is not so listed, the average of the representative bid and asked prices quoted
in the NASDAQ System as of 4:00 P.M., New York time, or, if on any day such
security is not quoted in the NASDAQ System, the average of the highest bid and
lowest asked prices on such day in the domestic over-the-counter market as
reported by the National Quotation Bureau, Incorporated or any similar successor
organization, in each such case averaged over a period of 30 days consisting of
the day as of which the "Market Price" is being determined and the 29
consecutive Business Days prior to such day. If at any time such security is not
listed on any securities exchange or quoted in the NASDAQ System or the
over-the-counter market, the "Market Price" shall be the fair value thereof
determined jointly by the Company and the Investor Agents. If such parties are
unable to reach agreement within a reasonable period of time, such fair value
shall be determined by an independent appraiser experienced in valuing
securities jointly selected by the Company and the Investor Agents. The
determination of such appraiser shall be final and binding upon the parties, and
the Company shall pay the fees and expenses of such appraiser.

                                       2
<PAGE>

         "OPTION" has the meaning set forth in Section 2.1(a).

         "OPTION PRICE" has the meaning assigned thereto in Section 2.1(a).

         "PREFERRED STOCK" means the Series B Convertible Preferred Stock of the
Company, or any other capital stock of the Company into which such stock is
reclassified or reconstituted.

         "PREMIUM ACQUISITION" means the consummation of an Acquisition that was
the subject of an Acquisition Proposal pursuant to which the holders of the
Company's outstanding Common Stock and Class B Common Stock receive stock, cash
or other consideration having a value on a per share basis at least equal to
110% of the Market Price of the Common Stock on the day the Company first
received such Acquisition Proposal.

         "PURCHASER(S)" has the meaning assigned thereto in the Preamble and
their successors and permitted assigns.

         "PURCHASER PREFERRED STOCK" means the Preferred Stock and the Series A
Preferred Stock.

         "PURCHASER REGULATORY EVENT" means any event in which any Purchaser
becomes subject to regulation as a "carrier," a "telephone company," a "common
carrier," a "public utility," or otherwise under any applicable law or
governmental regulation, federal, state, or local, as a result of the purchase
of the Series A Preferred Stock pursuant to the Purchase Agreement, the purchase
of the Preferred Stock pursuant to this Agreement and the execution and delivery
of the Transaction Documents (as defined in the Purchase Agreement) by the
parties thereto at the closing under the Purchase Agreement.

         "REQUISITE HOLDERS" has the meaning assigned thereto in Section 9.4.

         "SERIES A DESIGNATION" means the Certificate of Designation of the
Company relating to the Series A Preferred Stock filed with the Secretary of
State of Delaware as of the date hereof.

         "SERIES A PREFERRED STOCK" means the Series A Convertible Preferred
Stock of the Company or any other capital stock of the Company into which such
stock is reclassified or reconstituted.

                                       3
<PAGE>

         "SERIES B DESIGNATION" means the Certificate of Designation relating to
the Preferred Stock attached as Exhibit A hereto.

         "SERIES C DESIGNATION" means the Certificate of Designation of the
Company relating to the Series C Preferred Stock to be filed with the Secretary
of State of the State of Delaware in such form as is permitted by the Purchase
Agreement, as amended, supplemented or otherwise modified.

         "SERIES C PREFERRED STOCK" means the Series C Convertible Preferred
Stock of the Company or any other capital stock of the Company into which such
stock is reclassified or reconstituted.


                                   ARTICLE II

                          GRANT AND EXERCISE OF OPTION

         2.1.     GRANT AND EXERCISE OF OPTION; EXERCISE PERIOD.

         (a) The Company hereby grants to each Purchaser named on Schedule 1
hereto an option (the "Option") to purchase, subject to the terms hereof, that
number of shares of Preferred Stock set forth opposite such Purchaser's name on
Schedule 1, at a price of $1,000 per share (the "Option Price"). In the event
some or all of the Purchasers desire to exercise the Option, such Purchasers
shall send to the Company a written notice (the "Exercise Notice" ) specifying
(i) the total number of shares of Preferred Stock each such Purchaser will
purchase pursuant to such exercise and (ii) a date not earlier than five
Business Days nor later than 20 Business Days (subject to extension to satisfy
closing conditions hereunder) from the date of the Exercise Notice for the
closing of such purchase pursuant to Section 2.2. Subject to the provisions of
Section 2.1(c), the Option may be exercised, in whole or in part, at any one
time; provided that the Option may not be exercised in part unless the combined
Option exercises pursuant to the Exercise Notice provide for the purchase of at
least 25,000 shares of Preferred Stock.

         (b) Notwithstanding the provisions of Section 2.1(a), the Company shall
not be obligated to issue and sell any Preferred Stock pursuant to an Exercise
Notice if, within five Business Days of receipt of such notice, the Company
delivers a certificate to the Investor Agents executed by an Executive Officer
stating that, as of the date of receipt of the Exercise Notice, the Company had
received an Acquisition Proposal and describing the material terms of such
Acquisition Proposal (the "Proposal Notice") and provides the Investor Agents
with sufficient documentation to enable them to determine whether the proposed
transaction meets the criteria set forth in the definition of Acquisition
Proposal. If the Company timely delivers a Proposal Notice to the Investor
Agents, the Exercise Notice shall be deemed withdrawn without further action by
the Company or the Purchasers that submitted the Exercise Notice. In the event
(i) the Company terminates discussions with respect to the Acquisition Proposal
that was the subject of the Proposal Notice or (ii) the proposed transaction no
longer meets the criteria set forth in the definition of Premium Acquisition,
the Company shall promptly notify the Investor Agents of that fact in writing
(the "Termination Notice"), in which event the Option may again be exercised,
subject to the terms hereof, including the provisions of this Section 2.1(b) and
Section 2.1(c); provided, however, that in the event of an exercise of the
Option following receipt by the Investor Agents of a Termination Notice pursuant
to clause (ii), the Company shall not close such proposed transaction prior to
the closing of the Option pursuant to Section 2.2. In the event the Company
consummates an Acquisition described in an Acquisition Proposal that was the
subject of a Proposal Notice, it shall promptly notify the Investor Agents of
that fact in writing (the "Consummation Notice") and shall provide the
Purchasers with such documentation as reasonably requested by the Purchasers to
enable them to determine whether such Acquisition constitutes a Premium
Acquisition.

                                       4
<PAGE>

         (c) The Option granted hereunder shall be exercisable in accordance
with the terms hereof by delivery of an Exercise Notice at any time during the
period beginning on the date of this Agreement and ending on April 11, 2001 (the
"Exercise Period"); provided that if the exercise of the Option is deemed to be
withdrawn by the delivery of a Proposal Notice by the Company pursuant to
Section 2.1(b) and either (i) the Investor Agents have received a Termination
Notice with respect to such Proposal Notice or (ii) the Acquisition described in
the Acquisition Proposal that was the subject of such Proposal Notice is
consummated and such Acquisition is not a Premium Acquisition, the Option may be
exercised by delivery of an Exercise Notice at any time until the later of the
expiration of the Exercise Period or 30 days after the receipt by the Investors
Agents of the Termination Notice or Consummation Notice with respect to such
Acquisition, as applicable; and, provided, further, that if the exercise of the
Option is deemed to be withdrawn by the delivery of a Proposal Notice pursuant
to Section 2.1(b) and the Acquisition described in the Acquisition Proposal that
was the subject of such Proposal Notice is consummated and such Acquisition is a
Premium Acquisition, the Option, and the right of any Purchaser to exercise the
Option, shall automatically terminate.

         2.2 CLOSING. The issuance and purchase of the Preferred Stock upon the
exercise of the Option shall take place at the Closing (the "Closing") to be
held at the offices of Moore & Van Allen, PLLC, Charlotte, North Carolina, at
10:00 a.m., on the date specified in the Exercise Notice, or at such other time
and place as the Company and the Purchasers exercising the Option may agree in
writing (the "Closing Date"). At the Closing, the Company shall deliver to the
Purchasers certificates representing the number of shares of the Preferred Stock
specified in the Exercise Notice against delivery to the Company by the
Purchasers of the Option Price therefor by wire transfer of immediately
available funds.


                                   ARTICLE III

             CONDITIONS TO THE OBLIGATION OF THE PURCHASERS TO CLOSE

         The obligation of each Purchaser to purchase the number of shares of
Preferred Stock set forth in the Exercise Notice at the Closing, to pay the
Option Price therefor at the Closing and to perform any other obligations
hereunder shall be subject to the reasonable satisfaction as determined by each
Purchaser of the following conditions on or before the Closing Date:

                                       5
<PAGE>

         3.1 REPRESENTATIONS AND WARRANTIES. The representations and warranties
of the Company contained in Section 5 hereof shall be true and correct (a) when
made and (b) on and as of the Closing Date as if made on and as of such date
except for such changes to Schedules 5.9 and 5.10 as are permitted by the terms
of the Transaction Documents and set forth on revised Schedules 5.9 and 5.10
provided to the Purchasers at the Closing.

         3.2 COMPLIANCE WITH THIS AGREEMENT. The Company shall have performed
and complied in all material respects with all of the agreements, obligations,
covenants and conditions set forth in this Agreement that are required to be
performed or complied with by the Company on or before the Closing Date.

         3.3 OFFICER'S CERTIFICATE. Each Purchaser shall have received a
certificate dated as of the Closing Date from the chief executive officer and
chief financial officer of the Company, substantially in the form of Exhibit B,
to the effect that (a) all representations and warranties of the Company
contained in this Agreement are true and correct, (b) the Company is not in
violation in any material respect of any of the covenants contained in this
Agreement or any other Transaction Document, and (c) all conditions precedent to
the Closing to be performed by the Company have been duly performed in all
material respects.

         3.4 SECRETARY'S CERTIFICATE, GOOD STANDING CERTIFICATES. Each Purchaser
shall have received a certificate from the Company dated the Closing Date and
signed by the Secretary or an Assistant Secretary of the Company, substantially
in the form of Exhibit C, certifying (a) that the attached copies of the
Certificate of Incorporation, Bylaws or other applicable governance documents
and resolutions of the Board of Directors of the Company (i) authorizing the
issuance of the Preferred Stock pursuant to this Agreement and the issuance of
any Common Stock upon conversion thereof and (ii) approving this Agreement and
the transactions contemplated hereby to which it is a party, are all true,
complete and correct and remain unamended and in full force and effect, and (b)
as to the incumbency and specimen signature of each officer of the Company
executing any document delivered in connection with this Agreement on behalf of
the Company.

         3.5 PAYMENT OF FEES. There shall have been paid by the Company (a) to
Bain Capital Partners VI, L.P., a funding fee equal to 1% of the amount funded
by Bain Capital CLEC Investors, L.L.C. at the Closing, (b) to Thomas H. Lee
Equity Advisors IV, L.P. a funding fee equal to 1% of the amount funded by all
Purchasers other than Bain Capital CLEC Investors, L.L.C. at the Closing and (c)
to each Purchaser all legal fees and expenses required to be paid or reimbursed
to such Purchaser by the Company pursuant to Section 9.11 of the Purchase
Agreement. In addition, the Company shall have paid in full all fees due to
First Union Securities, Inc. in connection with the transactions contemplated by
this Agreement as of the Closing.

         3.6 PURCHASE PERMITTED BY APPLICABLE LAWS. The acquisition of and
payment for the Preferred Stock to be acquired by each Purchaser at the Closing
and the consummation of the transactions contemplated hereby at the Closing (a)
shall not be prohibited by any Requirement of Law, and (b) shall not subject any
Purchaser to any penalty or, in its reasonable judgment, other adverse condition
under or pursuant to any Requirement of Law.

                                       6
<PAGE>

         3.7 HSR CLEARANCE. Any required clearance under the Hart-Scott-Rodino
Act to sell the Preferred Stock upon the terms of this Agreement shall have been
obtained.

         3.8 SERIES B DESIGNATION. On or prior to the Closing, the Series B
Designation for the number of shares of Preferred Stock to be delivered at the
Closing, including shares of Preferred Stock issuable as preferential dividends
with respect thereto, shall have been duly filed with the Secretary of State of
the State of Delaware, all in accordance with the applicable provisions of the
DGCL, and the Series B Designation shall constitute a legal and valid amendment
of the Certificate of Incorporation and, as of the Closing, the Certificate of
Incorporation shall not have been otherwise amended; provided, that if at any
time from the date of this Agreement until the Closing Date the Company shall
take any action that would have caused an adjustment in the $46.50 conversion
price in Section 4.2 of the Series B Designation pursuant to Sections 4.3, 4.4,
4.5 or 4.6 thereof if the Series B Preferred Stock had been outstanding, the
conversion price set forth in Section 4.2, at the time the Series B Designation
is filed with the Secretary of State of the State of Delaware on the Closing
Date, shall be the conversion price as so adjusted.

         3.9 PREFERRED STOCK CERTIFICATE. Each Purchaser shall have received
from the Company a duly executed preferred stock certificate, substantially in
the form of Exhibit D, dated the Closing Date representing the number of shares
of Preferred Stock purchased by it at the Closing.

         3.10 REQUIRED CONTRACTUAL CONSENTS. The Company shall have received any
consents required pursuant to the terms of any material Contractual Obligation
in connection with the delivery of the Preferred Stock at the Closing.

         3.11 REQUIRED GOVERNMENTAL CONSENTS. The Company shall have received
all Regulatory Authorizations and other Governmental Authority approvals or
consents required in connection with the delivery of the Preferred Stock at the
Closing.

         3.12 LISTING OF SHARES. The Company shall have filed with The Nasdaq
Stock Market notice of the maximum number of shares of Common Stock potentially
issuable pursuant to the terms of the Series B Designation as of the Closing
Date other than any such shares as may be issuable upon an adjustment in the
conversion price of the Preferred Stock after the Closing Date.

         3.13 OPINIONS OF COUNSEL. The Purchasers shall have received (a) from
Moore & Van Allen, PLLC, special legal counsel for the Company, a favorable
opinion as of the Closing Date, to the effect that: (i) the Company is duly
organized as a corporation under the DGCL; (ii) the Company is validly existing
and in good standing in the jurisdiction of its incorporation and has the
requisite corporate power to own or lease and operate its property, and to carry
on its business as currently conducted; (iii) the issuance of the Preferred
Stock, including the issuance of Preferred Stock as preferential dividends
pursuant to the Series B Designation, has been duly authorized by all corporate
action required under the Company's Organizational Documents; (iv) the Series B
Designation has been duly authorized by all corporate action required under the
Company's Organizational Documents and filed with the Secretary of State of
Delaware; (v) upon issuance at the Closing, the Preferred Stock will be validly
issued, fully paid and nonassessable, and will not have been issued in violation
of or be subject to any preemptive rights, and the issuance of the shares of
Common Stock issuable upon conversion of the Preferred Stock has been duly
authorized and such shares have been duly reserved for issuance, and upon
issuance will be validly issued, fully paid and nonassessable, and will not have
been issued in violation of or be subject to any preemptive rights; and (b) from
Swidler Berlin Shereff Friedman, LLP, special regulatory counsel to the Company,
a favorable opinion as of the Closing Date, to the effect that (i) no consents
or approvals of the FCC or any PUC are required for the purchase of the
Preferred Stock pursuant to this Agreement and (ii) the purchase of the
Preferred Stock pursuant to this Agreement will not, in and of itself, subject
the Purchasers to regulation as common carriers or telephone companies under the
Communications Act (as defined in such opinion) in those states in which the
Company and its Subsidiaries are certified to operate as of the Closing.

                                       7
<PAGE>

         3.14 REGULATORY EVENTS. No Regulatory Event or Purchaser Regulatory
Event shall have occurred and be continuing or shall occur as a result of the
purchase of the Preferred Stock at the Closing.


                                   ARTICLE IV

              CONDITIONS TO THE OBLIGATION OF THE COMPANY TO CLOSE

         The obligations of the Company to issue and sell the Preferred Stock
pursuant to the Exercise Notice at the Closing and to perform its other
obligations hereunder at the Closing shall be subject to the satisfaction as
determined by the Company of the following conditions on or before the Closing
Date:

         4.1 REPRESENTATIONS AND WARRANTIES TRUE. The representations and
warranties of each of the Purchasers contained in Section 6 hereof shall be true
and correct on and as of the Closing Date as if made on and as of such date.

         4.2 COMPLIANCE WITH THIS AGREEMENT. Each of the Purchasers shall have
performed and complied in all material respects with all of its agreements and
conditions set forth or contemplated herein that are required to be performed or
complied with by each of the Purchasers on or before the Closing Date.

         4.3 ISSUANCE PERMITTED BY REQUIREMENTS OF LAWS. The issuance of the
Preferred Stock to be issued by the Company pursuant to the Exercise Notice at
the Closing and the consummation of the transactions contemplated hereby at the
Closing (a) shall not be prohibited by any Requirement of Law and (b) shall not
subject the Company to any penalty or, in its reasonable judgment, other onerous
condition under or pursuant to any Requirement of Law.

         4.4 HSR CLEARANCE. Any required clearance under the Hart-Scott-Rodino
Act to acquire the Preferred Stock pursuant to the Exercise Notice upon the
terms of this Agreement shall have been obtained.

                                       8
<PAGE>

         4.5 OPINION OF COUNSEL. If the rights of any Purchaser to purchase
Preferred Stock hereunder have been Transferred to a Permitted Transferee, such
Permitted Transferee or Permitted Transferees shall have delivered to the
Company an opinion dated the Closing Date from the Permitted Transferees'
counsel, Ropes & Gray, in form and substance satisfactory to the Company and its
counsel, to the effect that each such Permitted Transferee's performance of this
Agreement was duly authorized by the requisite corporate, fiduciary, limited
liability company or partnership action required under its Organizational
Documents and applicable state laws.


                                    ARTICLE V

                  REPRESENTATIONS AND WARRANTIES OF THE COMPANY

         The Company hereby represents and warrants to the Purchasers as
follows:

         5.1 ORGANIZATION AND QUALIFICATION. Each of the Company and its
Subsidiaries is duly organized, validly existing and in good standing under the
laws of its state of organization. Each of the Company and its Subsidiaries is
duly qualified to do business and in good standing in each jurisdiction in which
the failure to receive or retain such qualification would reasonably be expected
to have a Material Adverse Effect. As to any such entity that is a limited
liability company, each manager is duly organized, validly existing, in good
standing under the laws of its state of organization, and duly qualified to do
business and in good standing in each jurisdiction in which the failure to
receive or retain such qualification would reasonably be expected to have a
Material Adverse Effect.

         5.2 AUTHORITY AND AUTHORIZATION. Each of the Company and its
Subsidiaries has all requisite corporate or limited liability company right,
power, authority and legal right to carry on its business, to own or lease its
properties and to execute and deliver and perform its obligations under this
Agreement, and, in the case of the Company, to execute and deliver and to
perform its obligations under this Agreement and consummate the transactions
contemplated hereby. The Company's execution, delivery and performance of this
Agreement has been duly and validly authorized by all necessary corporate
proceedings on the part of the Company. Upon issuance, the Preferred Stock, and
any shares of such stock issuable as preferential dividends pursuant to the
terms thereof, will be validly issued, fully paid and nonassessable, and will
not have been issued in violation of or subject to any preemptive rights, and
the shares of Common Stock issuable upon conversion of the Preferred Stock, and
any shares of stock issuable as preferential dividends pursuant to the terms
thereof, have been duly authorized and, as of the date here of, will be reserved
for issuance, and upon issuance will be validly issued, fully paid and
nonassessable, and will not have been issued in violation of or be subject to
any preemptive rights.

                                       9
<PAGE>

         5.3 EXECUTION AND BINDING EFFECT. This Agreement has been duly and
validly executed and delivered by the Company, and constitutes the legal, valid
and binding obligations of the Company enforceable in accordance with its terms,
except as such enforceability may be limited by bankruptcy, insolvency,
reorganization, receivership, moratorium or other laws affecting creditors'
rights generally.

         5.4 GOVERNMENTAL AUTHORIZATIONS. Except as set forth on Schedule 5.4,
no authorization, consent, approval, license, exemption or other action by, and
no registration, qualification, designation, declaration or filing with, any
Governmental Authority is or will be necessary in connection with the execution
and delivery of this Agreement, the consummation by the Company of the
transactions herein contemplated, performance of or compliance by the Company
with the terms and conditions hereof or the legality, validity and
enforceability hereof.

         5.5 NO BROKERAGE FEES. Except for a fee payable to First Union
Securities, Inc., no brokerage or other fee, commission or compensation is to be
paid by the Company or any Subsidiary to any Person in connection with the
transactions hereunder except as contemplated herein.

         5.6 INVESTMENT COMPANY; PUBLIC UTILITY HOLDING COMPANY. Neither the
Company nor any of its Subsidiaries is an "investment company" or a "company
controlled by an investment company" or an "affiliated person" or "promoter" or
"principal underwriter" for, an "investment company," within the meaning of the
Investment Company Act of 1940, as amended, or a "holding company," or a
"subsidiary company" of a "holding company," or an "affiliate" of a "holding
company" or of a "subsidiary company" of a "holding company," within the meaning
of the Public Utility Holding Company Act of 1935, as amended.

         5.7 SECURITIES ACT. Based upon the representations and warranties of
each Purchaser in Section 6 of this Agreement, (i) the Preferred Stock to be
issued pursuant to an Exercise Notice, any Preferred Stock to be issued as
preferential dividends pursuant to the terms thereof and the Common Stock
issuable upon conversion of such Preferred Stock and (ii) the issuance by the
Company thereof, are not required to be registered under the Securities Act or
under the securities or blue sky laws of any state or jurisdiction.

         5.8 ABSENCE OF CONFLICTS. The consummation by the Company of the
transactions contemplated by this Agreement and the performance of or compliance
with the terms and conditions hereof by the Company will not, directly or
indirectly (and with or without notice or the passage of time or both), (a)
violate any Requirements of Law applicable to the Company or its Subsidiaries;
(b) conflict with or result in a breach of or a default under the Organizational
Documents of the Company or its Subsidiaries or any Contractual Obligation to
which the Company or its Subsidiaries is a party or by which such entity or its
properties are bound; (c) result in the creation or imposition of any Lien upon
any property (now owned or hereafter required); or (d) violate or conflict with,
or give any Governmental Authority the right to challenge the transactions
contemplated by this Agreement or revoke, withdraw, suspend, cancel, terminate
or modify, any Regulatory Authorization issued to or held by the Company or any
Subsidiary (other than as set forth on Schedule 5.8).

                                       10
<PAGE>

         5.9 TRANSACTIONS WITH AFFILIATES. No Affiliate and no officer or
director of either the Company or any its Subsidiaries or any individual related
by blood, marriage, adoption or otherwise to any such Affiliate, officer or
director, or any Person in which any such Affiliate, officer, director or
individual related thereto owns any material beneficial interest, is a party to
any agreement, contract, commitment or transaction with the Company or any of
its Subsidiaries or has any material interest in any material property used by
the Company or any of its Subsidiaries, except as set forth on Schedule 5.9.

         5.10 CAPITALIZATION. The authorized capital stock of the Company and
its Subsidiaries and the issued and outstanding shares thereof are as described
on Schedule 5.10. As of the Closing Date, all outstanding shares of capital
stock of the Company and its Subsidiaries will be duly authorized and validly
issued, fully paid, nonassessable and free and clear of any Lien created by the
Company or any Subsidiary thereof (other than Liens under the Senior Loan
Documents). Except as described in Schedule 5.10, no other class of capital
stock or other ownership interests of the Company or its Subsidiaries are
authorized or outstanding. Neither the Company nor any Subsidiary is subject to
any obligation (contingent or otherwise) to repurchase, redeem or otherwise
acquire its capital stock or any warrants, options or other rights to acquire
its capital stock, except pursuant to the Series A Designation and, when filed
with the Secretary of State of Delaware, the Series B Designation and Series C
Designation. The Company does not have any outstanding securities convertible
into capital stock of the Company (other than the Class B Common Stock and the
Series A Preferred Stock); and except for shares of Common Stock reserved for
issuance upon the exercise of outstanding warrants or in connection with the
Company Stock Option Plan, the Company does not have any shares of capital stock
reserved for issuance (other than shares of Common Stock reserved for issuance
upon conversion of the Class B Common Stock, the Preferred Stock, Series A
Preferred Stock and Series C Preferred Stock). Except as set forth on Schedule
5.10 and other than the Company's outstanding warrants and stock options and
this Agreement, the Company does not have any commitment to authorize, issue or
sell any of its capital stock or securities convertible into or exchangeable for
any of its capital stock. Neither the Company nor any of its Subsidiaries is a
party to any "phantom stock", employee stock option plan, other equity-based
incentive plan or similar agreement, other than the Company Stock Option Plan.
Schedule 5.10 sets forth the number of shares of capital stock reserved for
issuance upon the exercise of options granted or available to be granted under
the Company Stock Option Plan. Schedule 5.10 also lists all of the Company's
outstanding warrants to purchase capital stock. Except as set forth on Schedule
5.10, there are no preemptive or similar rights to purchase or otherwise acquire
equity securities of, or interests in, the Company or any of its Subsidiaries
pursuant to any Requirements of Law or Contractual Obligations applicable to the
Company or any of its Subsidiaries. Other than as set forth in the Transaction
Documents, there are no existing rights with respect to registration or sale or
resale under the Securities Act or the securities or blue sky laws of any state
or jurisdiction of any securities of the Company or any of its Subsidiaries.
Subject to the provisions of Section 3.8, the shares of Preferred Stock to be
issued to each Purchaser on the Closing Date, and any additional shares of
Preferred Stock to be issued as preferential dividends pursuant to the terms
thereof, will upon issuance to such Purchaser have the designation, preferences,
qualifications, limitations, restrictions and such special and relevant rights
as are set forth in the Series B Designation.

                                       11
<PAGE>

         5.11 COMMISSION FILINGS. Since April 23, 1998 (the date of the
Company's initial public offering), the Company has filed with the Commission,
on a timely basis, all registration statements, reports on Form 10-K, 10-Q and
8-K, proxy statements and information statements, and other documents that it
was required to file under the Securities Act or the Exchange Act. As of the
respective dates of such filings, none of the Company's filings with the
Commission contained (and the Company's most recent Form 10-K does not contain)
an untrue statement of a material fact or omitted (and the Company's most recent
Form 10-K does not omit) to state any material fact necessary to make any
statement of a material fact that it contained, in light of the circumstances in
which made, not misleading; and when filed with the Commission, each of such
filings with the Commission complied in all material respects with the
applicable requirements of the Securities Act or Exchange Act, as applicable.
The Company is eligible to file a registration statement on Form S-3 and has
taken all actions which would be required to permit sales of its securities
pursuant to Rule 144 under the Securities Act.

         5.12 LITIGATION. There is no pending or, to the Company's knowledge,
threatened action, suit or proceeding that challenges the transactions
contemplated by this Agreement or that would have the effect of preventing,
delaying, making illegal or otherwise interfering with the transactions
contemplated by this Agreement.

         5.13 NO DEFAULT. To the Company's knowledge, no event has occurred or
circumstance exists that (with or without notice or the passage of time or both)
would constitute or result in a violation or breach by the Company or any
Subsidiary of any provisions of the Transaction Documents.


                                   ARTICLE VI

                REPRESENTATIONS AND WARRANTIES OF THE PURCHASERS

         Each Purchaser as to itself and not as to any other Purchaser hereby
severally represents and warrants to the Company, as appropriate, as follows:

         6.1 AUTHORIZATION; NO CONTRAVENTION. Such Purchaser (unless an
individual) is duly organized, validly existing and in good standing as a
corporation, limited liability company or general or limited partnership under
the laws of the state of its incorporation or formation. The execution, delivery
and performance by such Purchaser of this Agreement (a) is within such
Purchaser's power and authority and has been duly authorized by all necessary
partnership, company or corporate action, (b) does not contravene the terms of
such Purchaser's organizational documents or any amendment thereof and (c) will
not violate, conflict with or result in any breach or contravention of any
material Contractual Obligation of such Purchaser, or any material Requirement
of Law directly relating to such Purchaser.

         6.2 BINDING EFFECT. This Agreement has been duly executed and delivered
by such Purchaser, and this Agreement constitutes the legal, valid and binding
obligation of such Purchaser enforceable against it in accordance with its
terms, except as enforceability may be limited by applicable bankruptcy,
insolvency, reorganization, moratorium, fraudulent conveyance or other similar
laws affecting the enforcement of creditors' rights generally or by general
equitable principles relating to enforceability.

                                       12
<PAGE>

         6.3 ACCREDITED INVESTOR; PURCHASE FOR OWN ACCOUNT. Such Purchaser is an
"accredited investor" within the meaning of Regulation D under the Securities
Act. The Preferred Stock to be issued pursuant to the terms of this Agreement,
any Preferred Stock to be issued as preferential dividends pursuant to the terms
thereof and the shares of Common Stock to be issued upon conversion of such
Preferred Stock are being or will be acquired for its own account and with no
intention of distributing or reselling such securities or any part thereof in
any transaction that would be in violation of the Securities Act or the
securities laws of any state, without prejudice, however, to the rights of such
Purchaser at all times to sell or otherwise dispose of all or any part of such
Preferred Stock or any shares of Common Stock under an effective registration
statement under the Securities Act, or under an exemption from such registration
available under the Securities Act. If such Purchaser should in the future
decide to dispose of such Preferred Stock or any shares of Common Stock issued
upon conversion of the Preferred Stock, such Purchaser understands and agrees
that it may do so only in compliance with the Securities Act and applicable
state securities laws, as then in effect. Such Purchaser agrees to the
imprinting, so long as required by law, of a legend on certificates representing
such Preferred Stock or any shares of Common Stock issued upon conversion of the
Preferred Stock to the following effect:

         "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
         REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR THE
         SECURITIES LAWS OF ANY STATE AND MAY NOT BE SOLD OR OTHERWISE DISPOSED
         OF EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH
         ACT AND APPLICABLE STATE SECURITIES LAWS OR PURSUANT TO AN APPLICABLE
         EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF SUCH ACT AND SUCH
         LAWS."

         The requirement to include the legend set forth above shall cease and
terminate as to any particular shares of Preferred Stock or Common Stock (a)
when, in the opinion of Ropes & Gray, or other counsel reasonably acceptable to
the Company, such legend is no longer required in order to assure compliance by
the Company with the Securities Act or (b) when such shares have been
effectively registered under the Securities Act or transferred pursuant to Rule
144. Whenever (x) such requirement shall cease and terminate as to any such
shares or (y) such shares shall be transferable under paragraph (k) of Rule 144,
the holder thereof shall be entitled to receive from the Company, without
expense, new certificates not bearing the legend set forth above.

         Such Purchaser also agrees to the imprinting, so long as required by
law, of a legend on certificates representing its shares of Preferred Stock:

         "THESE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO THE TERMS
         AND CONDITIONS, INCLUDING CERTAIN TRANSFER RESTRICTIONS, OF EACH OF
         THAT CERTAIN CORPORATE GOVERNANCE AGREEMENT, DATED AS OF APRIL 11,
         2000, AMONG THE COMPANY AND CERTAIN OF THE COMPANY'S STOCKHOLDERS. A
         COPY OF SUCH AGREEMENT MAY BE OBTAINED AT NO COST BY WRITTEN REQUEST TO
         THE COMPANY MADE BY THE HOLDER OF THIS CERTIFICATE."

                                       13
<PAGE>

         6.4 GOVERNMENTAL AUTHORIZATIONS. Except for clearance under the
Hart-Scott-Rodino Act, no notice to, consent of, or registration, filing or
declaration with, any Governmental Authority is required in connection with such
Purchaser's execution, delivery and performance of this Agreement and the
consummation of the transactions contemplated hereby.

         6.5 NO BROKERS OR FINDERS. Except as disclosed on Schedule 6.5, no
agent, broker, finder, or investment or commercial banker or other Person or
firm engaged by or acting on behalf of such Purchaser in connection with the
negotiation, execution or performance of this Agreement or the transactions
contemplated herein is or will be entitled to any brokerage or finder's or
similar fee or other commission as a result of this Agreement or such
transaction.

         6.6 VOTING AND OTHER AGREEMENTS. Such Purchaser does not have any
agreements, arrangements or understandings with any other Person (other than
with other Purchasers who are Affiliates of such Purchaser) with regard to
acquiring, holding, voting or disposing of the securities of the Company other
than as set forth in the Transaction Documents to which such Purchaser is a
party.


                                   ARTICLE VII

                                    COVENANTS

         7.1 HSR CLEARANCE. The Company and each of the Purchasers shall
cooperate with and provide each other, respectively, with any information that
each party reasonably requires and file such notices and responses as may be
necessary to enable each party to obtain any required clearance under the
Hart-Scott-Rodino Act in connection with the exercise of the Option. Each such
Purchaser required to obtain such clearance agrees to use all reasonable best
efforts to obtain such clearance as promptly as practicable on or prior to the
Closing Date.

         7.2 RESERVATION OF SHARES. The Company shall at all times reserve and
keep available out of the aggregate of its authorized but unissued shares, free
of preemptive rights, (i) such number of its duly authorized shares of Preferred
Stock as shall be sufficient to enable the Company to pay preferential dividends
pursuant to the terms of the Series B Designation with respect to all shares of
Preferred Stock issued thereunder, and (ii) such number of its duly authorized
shares of Common Stock as shall be sufficient to enable the Company to issue
Common Stock upon conversion of all such Preferred Stock.

         7.3 NOTICE OF ADJUSTMENTS. The Company shall give each of the
Purchasers written notice of any adjustments in the conversion price of the
Series B Designation contemplated by Section 3.8 within 10 Business Days of the
adjustment.

                                       14
<PAGE>

         7.4 GOVERNMENTAL CONSENTS. The Company shall use all commercially
reasonable efforts to obtain all of the authorizations, consents, approvals,
licenses and/or exemptions necessary in connection with the Closing hereunder,
including those listed on Schedule 5.4, on or prior to the Closing Date.

         7.5 CORPORATE CHANGE. Prior to the Closing Date, the Company shall:

         (a) prior to the consummation of any Corporate Change (as defined in
the Series B Designation) in which the Company is the successor or purchasing
corporation, make appropriate provisions (in form and substance reasonably
satisfactory to the Purchasers) such that each Purchaser shall have the right to
receive upon exercise of the Option, the Preferred Stock into which such Option
is exercisable with such terms and rights as would otherwise have been
applicable if the provisions of Section 4 and 5 of the Series B Designation had
been in full force and effect with respect to such shares since the date of this
Agreement; and

         (b) prior to the consummation of any Corporate Change in which the
successor or purchasing corporation is an entity other than the Company, make
appropriate provisions (in form and substance reasonably satisfactory to the
Purchasers) to ensure that each Purchaser shall have the right to receive upon
exercise of the Option, the number of shares of convertible preferred stock into
which such Option is exercisable to be issued by such successor or purchasing
corporation with substantially the same terms and rights as the Preferred Stock
as otherwise would have been applicable if the provisions of Section 4 and 5 of
the Series B Designation had been in full force and effect with respect to such
shares since the date of this Agreement.

         7.6 BEST EFFORTS. The Company will, and will cause each of its
Affiliates to, use its best efforts to cause the conditions set forth in Article
III to be satisfied on or prior to the Closing.

         7.7 ADJUSTMENTS IN CERTIFICATE OF DESIGNATION. The parties hereto agree
that upon the exercise of the Option, the terms of the Series B Designation
attached as Exhibit A hereto (including without limitation, the rate in clause
(i) of the definition of "Applicable Rate" and the number of "Dividend Payment
Dates" on which the Corporation is required to pay preferential dividends
through the issuance of additional shares of Preferred Stock) shall be adjusted
such that as of the twelfth dividend payment date under the Series A
Designation, the holders of each share of the Preferred Stock will have received
as preferential dividends thereon 0.19562 additional shares of Preferred Stock.
Such adjustments must be on terms reasonably satisfactory to each of the parties
hereto. The Series B Designation (as so adjusted) shall thereafter be referred
to herein as the "Series B Designation" and shall be filed with the Secretary of
State of Delaware in accordance with Section 3.8 hereof.

                                       15
<PAGE>

                                  ARTICLE VIII

                          INDEMNIFICATION; TERMINATION

         8.1 INDEMNIFICATION. Effective upon the Closing, the Company agrees to
indemnify and hold harmless the Purchasers and their Affiliates and their
officers, directors, agents, employees, subsidiaries, partners and controlling
Persons (each, a "Company Indemnified Party") to the fullest extent permitted by
law, from and against any and all losses, demands, actions, costs, claims,
damages, expenses (including reasonable fees, disbursements and other charges of
counsel) or other liabilities (collectively, "Company Liabilities") incurred or
suffered by such Company Indemnified Party resulting from or arising out of (i)
any misrepresentation or breach of any representation or warranty of the Company
in this Agreement, or any certificate or instrument delivered pursuant hereto,
(ii) any breach of any covenant or obligation of the Company in this Agreement,
or (iii) any investigation or proceeding against the Company or any Company
Indemnified Party that arises out of or in connection with this Agreement,
whether or not the transactions contemplated by this Agreement are consummated,
which investigation or proceeding requires the participation of, or is commenced
or filed against, any Company Indemnified Party because of this Agreement or the
transactions contemplated hereby; provided that (x) the Company shall not be
liable under Section 8.1(iii) to a Company Indemnified Party for any liabilities
resulting primarily from any actions that involved the gross negligence or
willful misconduct or any Company Indemnified Party or the breach by any Company
Indemnified Party of any representation, warranty, covenant or other agreement
of such Indemnified Party contained herein.

         8.2 NOTIFICATION. The Company Indemnified Party, under Section 8.1(iii)
will, promptly after the receipt of notice of the commencement of any action,
investigation, claim or other proceeding against such Company Indemnified Party
in respect of which indemnity may be sought from the Company under Section
8.1(iii), notify the Company in writing of the commencement thereof. The
omission of any Company Indemnified Party so to notify the Company of any such
action shall not relieve the Company from any liability which it may have to
such Company Indemnified Party under Section 8.1(iii) unless, and only to the
extent that, such omission results in the Company's forfeiture of substantive
rights or defenses or the Company is otherwise irrevocably prejudiced in
defending such proceeding. In case any such action, claim or other proceeding
shall be brought against any Company Indemnified Party and it shall notify the
Company of the commencement thereof, the Company shall be entitled to assume the
defense thereof at its own expense, with counsel satisfactory to the Company
Indemnified Party; provided, that any Company Indemnified Party may, at its own
expense, retain separate counsel to participate in such defense. Notwithstanding
the foregoing, in any action, claim or proceeding in which both the Company, on
the one hand, and a Company Indemnified Party, on the other hand, is, or is
reasonably likely to become, a party, such Company Indemnified Party shall have
the right to employ separate counsel at the Company's expense and to control its
own defense of such action, claim or proceeding if, (a) the Company has failed
to assume the defense and employ counsel as provided herein, (b) the Company has
agreed in writing to pay such fees and expenses of separate counsel or (c) in
the reasonable opinion of counsel to such Company Indemnified Party, a conflict
or likely conflict exists between the Company, on the one hand, and such Company
Indemnified Party, on the other hand, that would make such separate
representation advisable, provided, however, that the Company shall not in any
event be required to pay the fees and expenses of more than one separate counsel
(and if deemed necessary by such separate counsel, appropriate local counsel who
shall report to such separate counsel). The Company agrees that it will not,
without the prior written consent of a Company Indemnified Party, settle,
compromise or consent to the entry of any judgment in any pending or threatened
claim, action or proceeding relating to the matters contemplated hereby (if such
Company Indemnified Party is a party thereto or has been actually threatened to
be made a party thereto) unless such settlement, compromise or consent includes
an unconditional release of such Company Indemnified Party from all liability
arising or that may arise out of such claim, action or proceeding. The Company
shall not be liable for any settlement of any claim, action or proceeding
effected against a Company Indemnified Party without the prior written consent
of the Company.

                                       16
<PAGE>

                                   ARTICLE IX

                                  MISCELLANEOUS

         9.1 CLAIMS AND SUITS UNDER SECTION 8.1. No claim may be made or suit
instituted under Section 8.1 with respect to any breach of a representation or
warranty (except if it relates to Sections 5.1, 5.2, 5.3, 5.10 or if it relates
to fraud) after the date that is eighteen (18) months after the Closing Date,
unless the Company Indemnified Party has given the indemnifying party written
notice of such claim or suit (describing with reasonable specificity the amount
of and basis for such claim or suit) on or prior to such date.

         9.2 NOTICES. All notices, claims, demands and other communications
("Notices") provided for or permitted hereunder shall be made in writing and
shall be by registered or certified first class mail, return receipt requested,
telecopier, recognized overnight courier service or personal delivery:

         (a)      if to the Company:

                           US LEC Corp.
                           Transamerica Square
                           401 N. Tryon Street, Suite 1000
                           Charlotte, North Carolina 28202
                           Attention:  General Counsel
                           Telecopier:  (704) 319-3098

                  with a required copy to:

                           Moore & Van Allen, PLLC
                           100 North Tryon Street, Floor 47
                           Charlotte, North Carolina 28202-4003
                           Attention:  Barney Stewart III
                           Telecopier:  (704) 331-1151

                                       17
<PAGE>

         (b)      if to the Purchasers or the Investor Agents:

                           Bain Capital, Inc.
                           Two Copley Place
                           Boston, Massachusetts 02116
                           Attention:  Ian K. Loring
                           Telecopier:  (617) 572-3274

                           and to:

                           Thomas H. Lee Partners, L.P.
                           75 State Street, 26th Floor
                           Boston, Massachusetts 02109
                           Attention:  Anthony J. DiNovi
                           Telecopier (617) 227-3514

                  with a required copy to:

                           Ropes & Gray
                           One International Plaza
                           Boston, Massachusetts 02110-2624
                           Attention:  Philip J. Smith
                           Telecopier:  (617) 951-7050

         All Notices shall be deemed to have been duly given: when delivered by
hand, if personally delivered; when delivered by courier, if delivered by
commercial overnight courier service; five Business Days after being deposited
in the mail, postage prepaid, if mailed; and when receipt is acknowledged by the
individual to whom the telecopy is sent, if telecopied.

         9.3 SUCCESSORS AND ASSIGNS. This Agreement shall inure to the benefit
of and be binding upon the successors and permitted assigns of the parties
hereto. Subject to applicable securities laws and except as otherwise set forth
in the Transaction Documents (including, without limitation, the Corporate
Governance Agreement), the Purchasers may assign any of their rights under this
Agreement, to any Person who is a Permitted Transferee. The Company may not
assign any of its rights under this Agreement without the prior written consent
of the Purchasers. Except as provided in Article 9, no Person other than the
parties hereto and their successors and permitted assigns is intended to be a
beneficiary of this Agreement.

         9.4 DETERMINATIONS, REQUESTS OR CONSENTS. Any amendment, supplement or
modification of or to any provision of this Agreement, any waiver of any
provision of this Agreement, and any consent to any departure of the Company
from the terms of any provision of this Agreement, shall be effective (a) only
if it is made or given in writing and signed by the Company and the Required
Holders (as defined below) in accordance with this Section 9.4, and (b) only in
the specific instance and for the specific purpose for which made or given. All
determinations, requests, consents, waivers or amendments to be made by the
Purchasers in their opinion or judgment or with their approval or otherwise
pursuant to this Agreement shall be made at any time prior to the Closing by the
holders of at least 51% of the Series A Convertible Preferred Stock then
outstanding, and following the Closing by the holders of at least 51% of the
Purchaser Preferred Stock then outstanding (the "Required Holders").

                                       18
<PAGE>

         9.5 COUNTERPARTS. This Agreement may be executed in any number of
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same agreement.

         9.6 HEADINGS. The headings in this Agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof.

         9.7 GOVERNING LAW. This agreement shall be governed by and construed in
accordance with the laws of the State of Delaware without regard to the
principles of conflicts of law of such state.

         9.8 SEVERABILITY. If any one or more of the provisions contained
herein, or the application thereof in any circumstance, is held invalid, illegal
or unenforceable in any respect for any reason, the validity, legality and
enforceability of any such provision in every other respect and of the remaining
provisions hereof shall not be in any way impaired, unless the provisions held
invalid, illegal or unenforceable shall substantially impair the benefits of the
remaining provisions hereof.

         9.9 RULES OF CONSTRUCTION. Unless the context otherwise requires, "or"
is not exclusive, and references to sections or subsections refer to sections or
subsections of this Agreement. All pronouns and any variations thereof refer to
the masculine, feminine or neuter, singular or plural, as the context may
require.

         9.10 ENTIRE AGREEMENT. This Agreement, together with the exhibits
hereto and the other Transaction Documents, is intended by the parties as a
final expression of their agreement and intended to be a complete and exclusive
statement of the agreement and understanding of the parties hereto in respect of
the subject matter contained herein and therein. There are no restrictions,
promises, warranties or undertakings, other than those set forth or referred to
herein or therein. This Agreement, together with the exhibits hereto, and the
other Transaction Documents supersede all prior contemporaneous agreements and
understandings between the parties with respect to such subject matter.

         9.11 FURTHER ASSURANCES. Each of the parties shall execute such
documents and perform such further acts (including, without limitation,
obtaining any consents, exemptions, authorizations, or other actions by, or
giving any notices to, or making any filings with, any Governmental Authority or
any other Person) as may be reasonably required or desirable to carry out or to
perform the provisions of this Agreement.


                           [Signature Pages To Follow]


                                       19
<PAGE>



                                       20
<PAGE>

         IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed as of the date first above written.

                                  US LEC CORP.


                                    By: /s/ Michael K. Robinson
                                         Name:  Michael K. Robinson
                                                -----------------------------
                                         Title: Executive Vice President and
                                                  Chief Financial Officer


                                    BAIN CAPITAL CLEC INVESTORS, L.L.C.


                                    By:      Bain Capital Fund VI, L.P.,
                                             its Administrative Member
                                    By:      Bain Capital Partners VI, L.P.,
                                             its General Partner
                                    By:      Bain Capital Investors VI, Inc.,
                                             its general partner


                                    By: /s/ Michael A. Krupka
                                        -----------------------------
                                         Name:  Michael A. Krupka
                                         Title: Managing Director


                                    THOMAS H. LEE EQUITY FUND IV, L.P.

                                    By:      THL Equity Advisors IV, LLC,
                                             -----------------------------
                                             its general partner


                                    By: /s/ Anthony J. DiNovi
                                        -----------------------------
                                         Name:  Anthony J. DiNovi
                                         Title: Managing Director


                                    THOMAS H. LEE FOREIGN FUND IV-B, L.P.

                                    By:      THL Equity Advisors IV, LLC,
                                             its general partner


                                    By: /s/ Anthony J. DiNovi
                                        -----------------------------
                                         Name:  Anthony J. DiNovi
                                         Title: Managing Director


                                       21
<PAGE>

                                    THOMAS H. LEE FOREIGN FUND IV, L.P.

                                    By:      THL Equity Advisors IV, LLC,
                                             its general partner


                                    By: /s/ Scott M. Sperling
                                        -----------------------------
                                         Name:  Scott M. Sperling
                                         Title: Managing Director


                                    PUTNAM INVESTMENTS, INC.


                                    By: /s/ William H. Woolverton
                                        -----------------------------
                                         Name:  William H. Woolverton
                                         Title: Managing Director


                                    1997 THOMAS H. LEE NOMINEE TRUST


                                    By: /s/ Gerald Wheeler
                                        -----------------------------
                                        Trustee


                                    THOMAS H. LEE CHARITABLE INVESTMENT L.P.


                                    By: /s/ Thomas H. Lee
                                        -----------------------------
                                         Name:  Thomas H. Lee
                                         Title: President

                                       22
<PAGE>


                                    /s/ David V. Harkins
                                    -----------------------------
                                    DAVID V. HARKINS


                                    THE HARKINS 1995 GIFT TRUST


                                    By: /s/ Sheryll J. Harkins
                                        -----------------------------
                                         Trustee


                                    /s/ Scott A. Schoen
                                    -----------------------------
                                    SCOTT A. SCHOEN


                                    /s/ C. Hunter Boll
                                    -----------------------------
                                    C. HUNTER BOLL


                                    /s/ Scott M. Sperling
                                    -----------------------------
                                    SCOTT M. SPERLING


                                    /s/ Anthony J. DiNovi
                                    -----------------------------
                                    ANTHONY J. DINOVI


                                    /s/ Thomas M. Hagerty
                                    -----------------------------
                                    THOMAS M. HAGERTY


                                    /s/ Warren C. Smith, Jr.
                                    -----------------------------
                                    WARREN C. SMITH, JR.


                                    /s/ Seth W. Lawry
                                    -----------------------------
                                    SETH W. LAWRY


                                    /s/ Kent R. Weldon
                                    -----------------------------
                                    KENT R. WELDON


                                       23
<PAGE>

                                    /s/ Terrence M. Mullen
                                    -----------------------------
                                    TERRENCE M. MULLEN


                                    /s/ Todd M. Abbrecht
                                    -----------------------------
                                    TODD M. ABBRECHT


                                    /s/ Charles A. Brizius
                                    -----------------------------
                                    CHARLES A. BRIZIUS


                                    /s/ Scott Jaeckel
                                    -----------------------------
                                    SCOTT JAECKEL


                                    /s/ Soren Oberg
                                    -----------------------------
                                    SOREN OBERG


                                    /s/ Thomas R. Shepherd
                                    -----------------------------
                                    THOMAS R. SHEPHERD


                                    /s/ Wendy L. Masler
                                    -----------------------------
                                    WENDY L. MASLER


                                    /s/ Andrew D. Flaster
                                    -----------------------------
                                    ANDREW D. FLASTER


                                    ROBERT SCHIFF LEE 1988 IRREVOCABLE TRUST


                                    By: /s/ Charles W. Robins
                                        -----------------------------
                                         Trustee


                                    /s/ Stephen Zachary Lee
                                    -----------------------------
                                    STEPHEN ZACHARY LEE


                                       24
<PAGE>

                                    /s/ Charles W. Robins
                                    -----------------------------
                                    CHARLES W. ROBINS AS CUSTODIAN FOR
                                    JESSE LEE


                                    /s/ Charles W. Robins
                                    -----------------------------
                                    CHARLES W. ROBINS AS CUSTODIAN FOR
                                    NATHAN LEE


                                    /s/ Charles W. Robins
                                    -----------------------------
                                    CHARLES W. ROBINS


                                    /s/ James Westra
                                    -----------------------------
                                    JAMES WESTRA


                                    THL-CCI INVESTORS LIMITED
                                    PARTNERSHIP

                                    By:      THL Investment Management Corp.,
                                             its general partner


                                    By:
                                         -----------------------------
                                         Name:
                                         Title:


                                    /s/ Adam A. Abramson
                                    -----------------------------
                                    ADAM A. ABRAMSON


                                    /s/ Joanne M. Ramos
                                    -----------------------------
                                    JOANNE M. RAMOS

                                    /s/ P. Holden Spaht
                                    -----------------------------
                                    P. HOLDEN SPAHT


                                    /s/ Nancy M. Graham
                                    -----------------------------
                                    NANCY M. GRAHAM


                                    /s/ Gregory A. Ciongoli
                                    -----------------------------
                                    GREGORY A. CIONGOLI


                                       25
<PAGE>

                                    /s/ Wm. Matthew Kelly
                                    -----------------------------
                                    WM. MATTHEW KELLY


                                    /s/ Kevin F. Sullivan
                                    -----------------------------
                                    KEVIN F. SULLIVAN


                                    /s/ Diane M. Barriere
                                    -----------------------------
                                    DIANE M. BARRIERE


                                    /s/ Kim H. Oakley
                                    -----------------------------
                                    KIM H. OAKLEY


                                       26