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                                                                    EXHIBIT 4.31

                             STOCK TRADING AGREEMENT

     This Stock Trading Agreement, dated as of April 23, 2003 (as it may be
amended from time to time, this "AGREEMENT"), is made by Electric City Corp., a
Delaware corporation, and Richard Kiphart ("Kiphart").

                              W I T N E S S E T H:

     WHEREAS, Kiphart and the Company are parties to that certain Securities
Purchase Agreement, dated as of April 23, 2003 (as it may be amended from time
to time, the "KIPHART SECURITIES PURCHASE AGREEMENT"), whereby the Company has
agreed to sell and Kiphart has agreed to purchase shares of the Company's Common
Stock (as herein defined) together with warrants to purchase additional shares
of Common Stock; and

     WHEREAS, it is a condition precedent to the obligation of the Company to
issue and sell, and the obligation of Kiphart to purchase, such shares of Common
Stock and such warrants that the Parties hereto enter into this Agreement;

     NOW, THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt and adequacy of which are hereby
acknowledged, the Parties agree as follows:

                                    ARTICLE I
                                   DEFINITIONS

     1.1       DEFINED TERMS. The following additional terms when used in this
Agreement, including its preamble and recitals, shall, except where the context
otherwise requires, have the following meanings, such meanings to be equally
applicable to the singular and plural forms thereof:

          "AFFILIATE" means, as applied to any Person, any other Person
     controlling, controlled by or under common control with such Person. For
     purposes of this definition, "control" (including, with correlative
     meanings, the terms "controlled by" and "under common control with"), as
     applied to any Person, shall mean the possession, directly or indirectly,
     of the power to direct or cause the direction of the management and
     policies of any such other Person, whether through the ownership of voting
     securities or by contract or otherwise. With respect to individuals, the
     term Affiliate shall also include such individuals' parents, spouse,
     children or grandchildren.

          "AGREEMENT" shall have the meaning set forth in the preamble hereof.

          "AVERAGE DAILY TRADING VOLUME" with respect to any trading day, means
     the average daily trading volume of the Common Stock as reported on the
     American Stock Exchange (or, if not traded on the American Stock Exchange,
     any national securities exchange or automated quotation services on which
     the Common Stock is then listed for

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     trading) for the twenty (20) consecutive trading days ending on the date
     immediately prior to such trading day.

          "BLOCK SALE" means a sale of at least 10,000 shares of Subject Common
     Stock.

          "CLOSING DATE" means the date of closing under the Kiphart Securities
     Purchase Agreement and issuance to Kiphart of the shares of Common Stock
     and Kiphart Warrant as contemplated thereby.

          "CLOSING PRICE" means the closing price of the Common Stock as
     reported on the American Stock Exchange (or, if not traded on the American
     Stock Exchange, any national securities exchange or automated quotation
     services on which the Common Stock is then listed for trading).

          "COMMON STOCK" means and includes the Company's authorized common
     stock, par value $0.0001 per share.

          "COMPANY" shall have the meaning set forth in the preamble hereof.

          "KIPHART SECURITIES PURCHASE AGREEMENT" shall have the meaning set
     forth in the first WHEREAS clause hereof.

          "KIPHART WARRANT" means the Warrant Certificate to Purchase Shares of
     Common Stock dated April 23, 2003 and denominated as Warrant No. 41 issued
     by the Company to Kiphart pursuant to closing under the Kiphart Securities
     Purchase Agreement and exercisable for up to 125,974 shares of Common Stock
     (subject to adjustment as provided therein).

          "PARTIES" means all of the parties that are signatories to this
     Agreement.

          "PERSON" means and includes an individual, a corporation, a limited
     liability company, an association, a partnership, a trust or estate, a
     government or any department or agency thereof.

          "SUBJECT COMMON STOCK" means and includes all shares of Common Stock
     which Kiphart acquires pursuant to the Kiphart Securities Purchase
     Agreement or the Kiphart Warrant.

                                   ARTICLE II
                              TRADING RESTRICTIONS

     2.1  AGREEMENT FOR BENEFIT OF COMPANY. Kiphart hereby agrees that its
obligations under this Agreement are for the benefit of the Company and further
agrees that the Company shall be entitled to enforce Kiphart's obligations under
this Agreement.

     2.2  PUBLIC SALES. Kiphart shall be subject to the following trading
restrictions from time to time concerning his holdings of Subject Common Stock:

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          (a)  During the term of this Agreement and at any time the Closing
     Price on the then prior trading day is at least $1.00 per share but less
     than $2.00 per share, Kiphart may sell any of his Subject Common Stock into
     the public market, subject to the following conditions:

               (i)   the number of shares of Subject Common Stock sold by
          Kiphart on any trading day may not exceed twenty percent (20%) of the
          Average Daily Trading Volume;

               (ii)  the number of shares of Subject Common Stock sold by
          Kiphart into the public market in any three-month period may not
          exceed twenty percent (20%) of Kiphart's total holdings of Subject
          Common Stock, calculated assuming the exercise of all rights, options
          and warrants to purchase Subject Common Stock or securities
          convertible or exchangeable for shares of Subject Common Stock, and
          the conversion or exchange of all securities convertible or
          exchangeable for Subject Common Stock held as of the date of this
          Agreement (as adjusted for stock splits, stock combinations and the
          like); and

               (iii) Block Sales must be executed at a minimum price per share
          of ninety percent (90%) of the ask price as reported on the American
          Stock Exchange (or, if not traded on the American Stock Exchange, any
          national securities exchange or automated quotation services on which
          the Common Stock is then listed for trading).

          (b)  During the term of this Agreement and at any time the Closing
     Price on the then prior trading day is less than $1.00 per share, Kiphart
     may sell any of his Subject Common Stock into the public market, subject to
     the following conditions:

               (i)   the number of shares of Subject Common Stock sold by
          Kiphart on any trading day may not exceed twenty percent (20%) of the
          Average Daily Trading Volume; and

               (ii)  Block Sales must be executed at a minimum price per share
          of ninety percent (90%) of the ask price as reported on the American
          Stock Exchange (or, if not traded on the American Stock Exchange, any
          national securities exchange or automated quotation services on which
          the Common Stock is then listed for trading).

          (c)  Effective with the Closing Date and during the term of this
     Agreement, Kiphart agrees that he will not engage, either directly or
     indirectly, in short sales of the Subject Common Stock and represents and
     warrants that he has not engaged, either directly or indirectly, in short
     sales of the Subject Common Stock at any time prior to the Closing Date.
     Notwithstanding anything contained herein to the contrary, Kiphart shall
     have the right to create and maintain a short position in the Company's
     Common Stock so long as the amount of the short position does not exceed
     the number of shares of Subject Common Stock obtainable upon exercise of
     the Kiphart Warrant and the Kiphart Warrant is then held by Kiphart.

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     2.3  TRANSFER TO AFFILIATES. Notwithstanding anything in this Agreement to
the contrary, Kiphart may freely sell or otherwise transfer any Subject Common
Stock (or securities exercisable or exchangeable for or convertible into shares
of Subject Common Stock) which he owns to his Affiliates without such sale or
transfer being in violation of the terms of this Agreement; PROVIDED, HOWEVER,
that concurrently with any such transfer any such Affiliate shall become a party
to this Agreement and its ownership and sales of shares of Subject Common Stock
(or other securities exercisable or exchangeable for or convertible into shares
of Subject Common Stock) shall be aggregated with Kiphart's for purposes of
SECTION 2.2.

     2.4  TERM OF TRADING AGREEMENT. The term of this Agreement shall commence
on the Closing Date and terminate on the earlier of September 7, 2004 or the
date that the Company's Common Stock is no longer listed on any national
securities exchange or automated quotation services.

                                   ARTICLE III
                               GENERAL PROVISIONS

     3.1       LEGEND ON SHARE CERTIFICATES.

          (a)  All shares of Subject Common Stock that are subject to the terms
and provisions of ARTICLE II, in addition to such other legends as may be
required by law and any other legend required by any agreement or document
executed in connection with the closing under the Kiphart Securities Purchase
Agreement, shall bear the following legend:

          THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN
          REQUIREMENTS AS TO TRADING CONTAINED IN THE STOCK TRADING AGREEMENT,
          DATED AS OF APRIL 23, 2003, BETWEEN THE COMPANY AND THE HOLDER, A COPY
          OF WHICH IS ON FILE WITH THE SECRETARY OF THE COMPANY.

          (b)  Upon the termination of this Agreement or for sales in
conformance with the provisions of this Trading Agreement, Kiphart (or the
applicable purchaser) shall be entitled to receive, in exchange for any security
bearing the legend regarding this Agreement specifically set forth in SECTION
3.1(a), a security without such legend.

                                   ARTICLE IV
                                  MISCELLANEOUS

     4.1  INJUNCTIVE RELIEF. It is acknowledged that it is impossible to measure
in money the damages that would be suffered if Kiphart fails to comply with the
obligations imposed on him by this Agreement and that, in the event of any such
failure, the Company would be irreparably damaged and would not have an adequate
remedy at law. The Company shall, therefore, be entitled to injunctive relief
and/or specific performance to enforce such obligations of Kiphart, and if any
action should be brought in equity to enforce any of such provisions of this
Agreement, Kiphart shall not raise the defense that there is an adequate remedy
at law.

     4.2  GOVERNING LAW. Except as to matters governed by the General
Corporation Law

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of the State of Delaware and decisions thereunder of the Delaware courts
applicable to Delaware corporations, which shall be governed by such laws and
decisions, this Agreement shall be construed and enforced in accordance with,
and the rights of the Parties shall be governed by, the laws of the State of
Illinois.

     4.3  ENTIRE AGREEMENT; WAIVER. This Agreement contains the entire agreement
among the Parties hereto with respect to the subject matter hereof. No waiver of
any term or provision shall be effective unless in writing signed by the Party
to be charged in accordance herewith.

     4.4  BINDING EFFECT. This Agreement shall be binding on and inure to the
benefit of the Parties and, subject to the terms and provisions hereof, their
respective legal representatives, successors and assigns.

     4.5  INVALIDITY OF PROVISION. The invalidity or unenforceability of any
provision of this Agreement in any jurisdiction shall not affect the validity or
enforceability of the remainder of this Agreement in that jurisdiction or the
validity or enforceability of this Agreement, including that provision, in any
other jurisdiction.

     4.6  COUNTERPARTS. This Agreement may be executed in two or more
counterparts, all of which shall be deemed but one and the same instrument and
each of which shall be deemed an original, and it shall not be necessary in
making proof of this Agreement to produce or account for more than one such
counterpart for each of the parties hereto. Delivery by facsimile by any of the
Parties hereto of an executed counterpart of this Agreement shall be effective
as an original executed counterpart hereof and shall be deemed a representation
that an original executed counterpart hereof will be delivered.

     4.7  NOTICES. All notices, consents and other communications under this
Agreement shall be in writing and shall be deemed to have been duly given when
(a) delivered by hand, (b) sent by facsimile (with receipt confirmed), provided
that a copy is mailed by certified mail, return receipt requested, or (c) when
received by the addressee, if sent by Express Mail, Federal Express or other
reputable express delivery service (receipt requested), in each case to the
appropriate address and facsimile number set forth below (or to such other
address and facsimile number as a Party may designate as to itself by notice to
the other Party):

     (i)  If to the Company:     1280 Landmeier Road
                                 Elk Grove Village, IL 60007-2410
                                 Fax No. 847-437-4969
                                 Attention: Treasurer

     (ii) If to Kiphart: at the address set forth in the Kiphart Securities
Purchase Agreement.

     4.8  HEADINGS. The descriptive headings of the several paragraphs of this
Agreement are inserted for convenience only and do not constitute part of this
Agreement.

[Balance of page intentionally left blank; signature page follows.]

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     IN WITNESS WHEREOF, the Parties hereto have executed this Stock Trading
Agreement as of the day and year first above written.


ELECTRIC CITY CORP.

By:   /s/ John Mitola                       By:  /s/ Richard Kiphart
    ------------------------------              -----------------------------
Name:  John Mitola                                 Richard Kiphart
Title: Chief Executive Officer

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