13D Filing: MAST Capital and Great Elm Capital Group Inc. (GEC)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE
13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 6)

Great Elm
Capital Group, Inc.

(Name of Issuer)

Common Stock, $0.001 Par Value

(Title of Class of Securities)

39036P209

(CUSIP Number)

MAST Capital Management, LLC

31 St. James Avenue, 6^th Floor

Boston, MA 02116

(617)
375-3000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

September 18, 2017

(Date
of Event which Requires Filing of this Statement)

If the filing person has
previously filed a statement on Schedule 13G to report the acquisition which is the subject of this Schedule 13D, and is filing this schedule because of Sections 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following
box.  ☐

The information required on the remainder of this cover page shall not be deemed to be filed for the purpose of
Section 18 of the Securities Exchange Act of 1934 (Act) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

This Amendment No. 6 (this Amendment) to the Schedule 13D (the Schedule 13D) is
being filed on behalf of MAST Capital Management, LLC, a Delaware limited liability company (MAST Capital), and Mr. David J. Steinberg, the principal of MAST Capital (together with MAST Capital, the Reporting
Persons), relating to Common Stock, $0.001 Par Value (the Common Stock), of Great Elm Capital Group, Inc., a Delaware corporation (f/k/a Unwired Planet, Inc.) (the Issuer).

This Amendment relates to Common Stock of the Issuer purchased by Mr. Steinberg directly and by MAST Capital through the accounts of
certain private funds (collectively, the MAST Accounts) and also Common Stock held directly by MAST Capital. MAST Capital serves as the investment manager to the MAST Accounts and may direct the vote and disposition of 1,947,735 shares
of Common Stock held by the MAST Accounts. As the principal of MAST Capital, Mr. Steinberg may direct the vote and disposition of the 1,947,735 shares of Common Stock held by the MAST Accounts and the shares of Common Stock held directly by
MAST Capital.

The information set forth in response to each Item below shall be deemed to be a response to all Items where such
information is relevant. The Schedule 13D is supplementally amended as follows.

Item 4. Purpose of Transaction

On September 18, 2017 (the Effective Date), the Issuer, the Reporting Persons, and certain other parties related to the Issuer
and the Reporting Persons entered into a Separation Agreement (the Separation Agreement), pursuant to which the parties agreed to separate their organizations and amend and cancel certain agreements among them.

The following is a brief description of certain terms of the Separation Agreement, such description being qualified in its entirety by
reference to the full text of the Separation Agreement, which is attached as Exhibit 99.1 hereto and incorporated by reference herein.

Under the terms of the Separation Agreement on the Effective Date (a) the Reporting Persons and certain funds managed by MAST Capital
that are parties to the Separation Agreement (including the MAST Account) (the Mast Funds, and together with the Reporting Persons, the Standstill Parties) have agreed to certain standstill obligations for the Standstill
Period (as defined below), subject to certain exceptions set forth in the Separation Agreement regarding the Standstill Parties rights under the Separation Agreement, the Ancillary Agreements (as defined in the Separation Agreement), or the
Indaba Agreements (as defined in the Separation Agreement) and (b) during the Standstill Period, the Issuer has agreed that Hugh Steven Wilson will not serve as chairman of the board of directors of the Issuer (the Board). Under the
terms of the Separation Agreement, Standstill Period means the period from the Effective Date until the earlier of (i) the two year anniversary of the Effective Date or (ii) termination of the standstill obligations pursuant to
the terms of the Separation Agreement.

Under the terms of the Separation Agreement, (a) the Issuer affirmed its obligations and the
rights of Buyers (as defined in the Indaba Agreements) under the Indaba Agreements; and (b) the Mast Funds have agreed not to remove or replace either James Parmalee or Matthew Drapkin as an Initial Investor Director or
Additional Investor Director, in each case within the meaning of the Indaba Agreements, unless (i) the notice of removal is prior to the time that the Board (or applicable committee) has resolved to nominate and recommend
Mr. Parmelee or Mr. Drapkin for election as a director at a meeting of stockholders of the Issuer, and (ii) such removal is effective as of the conclusion of such meeting of stockholders.

In addition, under the terms of the Separation Agreement on the Effective Date, (a) the
Issuer and Mast Capital have agreed that the warrant, dated December 9, 2016, delivered to Mast Capital by the Issuer, is cancelled and replaced by an aggregate of 54,733 shares of Common Stock registered in Mast Capitals name;
(b) the Issuer and Mr. Steinberg have agreed that the Performance Share Award Agreement, dated November 3, 2016, between the Issuer and Mr. Steinberg, granting to Mr. Steinberg 220,923 performance-based restricted shares of
Common Stock, is cancelled and forfeited in full; (c) Mr. Steinberg has agreed to voluntarily resign from employment at Great Elm Capital Management, Inc., a Delaware corporation and subsidiary of the Issuer; (d) the Issuer has agreed
to grant Mast Capital the New Warrant (as defined in Item 5(a) below), the terms and conditions of which are described in Item 5(a) below; (e) the Issuer has agreed to provide (i) demand registration rights exercisable following the first
anniversary of the Effective Date if the New Warrant has been exercised, and (ii) piggy-back registration rights with respect to shares of Common Stock issued or issuable pursuant to the Separation Agreement; (f) the Issuer has, in
accordance with its Amended and Restated Certificate of Incorporation (the Certificate), approved the acquisition by Mast Capital (or its designee under the New Warrant) of any and all shares of Common Stock contemplated under the
Separation Agreement or the New Warrant, and has waived any and all other conditions, notice requirements and other limitations found in Article XIV of the Certificate affecting the acquisition of such shares; (g) the Board has granted an
exemption under the Issuers Tax Benefits Preservation Agreement, dated as of January 20, 2015, with respect to the acquisition by Mast Capital (or its designee under the New Warrant) of any and all shares of Common Stock contemplated by
the Separation Agreement or the New Warrant; and (h) certain parties to the Separation Agreement (including the Issuer and the Reporting Persons) have agreed to mutually release and forever discharge the other releasing parties from any and all
liability whatever arising out of, based upon or relating to actions or omissions occurring on or before the Effective Date, subject to certain limitations, including with respect to claims arising from the Separation Agreement, as set forth in the
Separation Agreement.

Item 5. Interest in Securities of the Issuer

(a) The aggregate percentage of Common Stock reported to be owned by the Reporting Persons is based upon 24,558,614 shares of Common Stock
outstanding, which is derived by adding (i) 24,139,631 shares of Common Stock outstanding as of September 1, 2017, as reported in the Issuers Form 10-K filed with the Securities and Exchange
Commission on September 19, 2017, (ii) the 54,733 shares of Common Stock issued to MAST Capital on the Effective Date pursuant to the terms of the Separation Agreement and (iii) 364,250 shares of Common Stock which could be issuable upon
exercise of the New Warrant, as described below.

MAST Capital (i) holds 54,733 shares of Common Stock, which were issued pursuant to
the Separation Agreement on the Effective Date, and (ii) as the investment manager of the MAST Accounts, may be deemed to beneficially own 1,947,735 shares of Common Stock held by the MAST Accounts.

On September 18, 2017, the Issuer issued to Mast Capital a warrant (the New Warrant) for Mast Capital (or one or more Mast
Funds, as Mast Capitals designee) to purchase up to 420,000 shares of Common Stock; provided, that Mast Capital (or its designee) may not purchase Common Stock pursuant to the New Warrant if such purchase would result in the Reporting Persons
beneficially owning more than 9.9% of the outstanding Common Stock. As of the date hereof, 364,250 shares of Common Stock could be issuable upon exercise of the New Warrant in compliance with such limitation. The New Warrant is exercisable from the
date that is ten trading days following the date of issuance of the New Warrant up to and until the expiration of the Standstill Period. The exercise price for the New Warrant is the simple average of the Weighted Average Price (as defined in the
New Warrant) of the Common Stock for the ten consecutive trading days ending on and including the trading day immediately prior to the date of the exercise of the New Warrant. The foregoing description of the New Warrant is qualified in its entirety
by reference to the full text of the New Warrant, which is attached as Exhibit 99.2 hereto and incorporated by reference herein.

The
total shares of Common Stock which may be deemed to be beneficially owned by MAST Capital are 2,366,718 shares of Common Stock, representing approximately 9.6% of the issued and outstanding shares of Common Stock of the Issuer.

Mr. Steinberg directly holds 64,584 shares of Common Stock. In addition, Mr. Steinberg,
as the principal of MAST Capital, may be deemed to beneficially own the 2,366,718 shares of Common Stock which are beneficially owned (or may be deemed to be beneficially owned) by MAST Capital. The total shares of Common Stock which
Mr. Steinberg beneficially owns (or may be deemed to beneficially own) are 2,431,302, representing approximately 9.9% of the issued and outstanding shares of Common Stock of the Issuer.

MAST Capital and Mr. Steinberg disclaim beneficial ownership of the Common Stock held by the MAST Accounts except to the extent of their
pecuniary interest therein. Mr. Steinberg declaims beneficial ownership of the Common Stock held by MAST Capital except to the extent of his pecuniary interest therein.

(b) MAST Capital and Mr. Steinberg have the shared power to vote and dispose of the Common Stock owned by the MAST Accounts and MAST
Capital reported in this Schedule 13D. Mr. Steinberg has the sole power to vote and dispose of the Common Stock directly owned by him reported in this Schedule 13D.

The filing of this Schedule 13D shall not be construed as admission that MAST Capital or Mr. Steinberg is, for the purposes of
Section 13(d) or 13(g) of the Act, or otherwise, the beneficial owner of any of the 1,947,735 shares of Common Stock owned by the MAST Accounts or that Mr. Steinberg is, for the purposes of Section 13(d) or 13(g) of the Act, or
otherwise, the beneficial owner of any of the shares of Common Stock owned by MAST Capital. Pursuant to Rule 13d-4, MAST Capital and Mr. Steinberg disclaim all such beneficial ownership.

(c) Pursuant to, and in consideration of the agreements set forth in, the Separation Agreement, on the Effective Date, the Issuer issued (i)
54,733 shares of Common Stock to MAST Capital and (ii) the New Warrant to MAST Capital (in the amount set forth in Item 5(a)).

(d)
The 1,947,735 shares of Common Stock held by the MAST Accounts consists of the following amounts: 1,947,735 shares of Common Stock held by Mast Admiral Master Fund LP.

(e) Not applicable.

Item 6.
Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer

Reference is made to the
Separation Agreement as described above under Item 4 and attached hereto as Exhibit 99.1.

Reference is made to the New Warrant as
described above under Item 5(a) and attached hereto as Exhibit 99.2.

On September 18, 2017, the Issuer and Mast Capital entered into
a Share Registration Agreement (the Share Registration Agreement) pursuant to which the Issuer granted to Mast Capital (i) demand registration rights exercisable following the first anniversary of the Effective Date if the New
Warrant has been exercised, and (ii) piggy-back registration rights with respect to shares of Common Stock issued or issuable pursuant to the Separation Agreement. This description of the Share Registration Agreement is qualified in its
entirety by reference to the full text of the Share Registration Agreement, which is attached as Exhibit 99.3 hereto and incorporated by reference herein.

Item 7. Material to be Filed as Exhibits

SIGNATURES

After reasonable inquiry and to the best of each of the undersigneds knowledge and belief, each of the undersigned, severally and not jointly, certified
that the information set forth in this statement is true, complete and correct.

Dated: September 20, 2017