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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549



                                  SCHEDULE 13G



                    UNDER THE SECURITIES EXCHANGE ACT OF 1934
                               (AMENDMENT NO. 3)*




                     BlackRock Corporate High Yield Fund III

--------------------------------------------------------------------------------

                                (NAME OF ISSUER)

                                  Common Stock
--------------------------------------------------------------------------------
                         (TITLE OF CLASS OF SECURITIES)




                                    09255M104
                                ===============
                                 (CUSIP NUMBER)

                                December 31, 2009

--------------------------------------------------------------------------------
             (DATE OF EVENT WHICH REQUIRES FILING OF THIS STATEMENT)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

|X| Rule 13d-1(b)

| | Rule 13d-1(c)

| | Rule 13d-1(d)

*  The remainder of this cover page shall be filled out for a reporting person's
   initial filing on this form with respect to the subject class of securities,
   and for any subsequent amendment containing information which would alter the
   disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of (S) 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).


CUSIP No. 09255M104
--------------------------------------------------------------------------------
1. Names of Reporting Persons.

     Claymore Securities Defined Portfolios, Series 224, 273, 334,
     378, 434 and 465
--------------------------------------------------------------------------------

                                       1


I.R.S. Identification Nos. of above persons (entities only):

     Claymore Securities Defined Portfolios, Series 224 -- Tax ID# 137450877
     Claymore Securities Defined Portfolios, Series 273 -- Tax ID# 137488925
     Claymore Securities Defined Portfolios, Series 334 -- Tax ID# 205639678
     Claymore Securities Defined Portfolios, Series 378 -- Tax ID# 137554782
     Claymore Securities Defined Portfolios, Series 434 -- Tax ID# 137573681
     Claymore Securities Defined Portfolios, Series 465 -- Tax ID# 137586082


--------------------------------------------------------------------------------
2. Check the Appropriate Box if a Member of a Group (See Instructions)
     (a) __
     (b) __
--------------------------------------------------------------------------------
3. SEC Use Only

--------------------------------------------------------------------------------
4. Citizenship or Place of Organization:

     Claymore Securities Defined Portfolios, Series 224, Lisle, IL
     Claymore Securities Defined Portfolios, Series 273, Lisle, IL
     Claymore Securities Defined Portfolios, Series 334, Lisle, IL
     Claymore Securities Defined Portfolios, Series 378, Lisle, IL
     Claymore Securities Defined Portfolios, Series 434, Lisle, IL
     Claymore Securities Defined Portfolios, Series 465, Lisle, IL

--------------------------------------------------------------------------------

   Number of     5.    Sole Voting Power
    Shares                     405,016
Beneficially by-----------------------------------------------------------------
   Owned by      6.    Shared Voting Power
     Each      -----------------------------------------------------------------
   Reporting     7.    Sole Dispositive Power
    Person                     405,016
     With:     -----------------------------------------------------------------
                 8.    Shared Dispositive Power
--------------------------------------------------------------------------------
9. Aggregate Amount Beneficially Owned by Each Reporting Person

                 405,016

--------------------------------------------------------------------------------
10. Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See
Instructions)

--------------------------------------------------------------------------------
11. Percent of Class Represented by Amount in Row (9)

                 1.08%

--------------------------------------------------------------------------------
12. Type of Reporting Person (See Instructions)

                 IV

--------------------------------------------------------------------------------

ITEM 1.        (a) Name of Issuer

                    BlackRock Advisors

               (b) Address of Issuer's Principal Executive Offices

                    P.O. Box 9011
                    Princeton, NJ 08543-9011

ITEM 2.        (a) Name of Person Filing

                    Claymore Securities, Inc. as Sponsor for the Filing Entities

                                       2


               (b) Address of Principal Business Office or, if none, Residence

                    2455 Corporate West Drive
                    Lisle, IL 60532

               (c) Citizenship

                    USA

               (d) Title of Class of Securities

                    Common Stock

               (e) CUSIP Number

                    09255M104

ITEM 3.        IF THIS STATEMENT IS FILED PURSUANT TO (S) (S) 240.13D-1 (B) OR
               240.13D-2(B) OR (C), CHECK WHETHER THE PERSON FILING IS A:

               (a) |X| Broker or dealer registered under section 15 of the Act
                   (15 U.S.C, 78o).

               (b) | | Bank as defined in section 3(a)(6) of the Act (15 U.S.C.
                   78c).

               (c) | | Insurance company as defined in section 3(a)(19) of the
                   Act (15 U.S.C. 78c).

               (d) | | Investment company registered under section 8 of the
                   Investment Company Act of 1940 (15 U.S.C 80a-8).

               (e) | |An investment adviser in accordance with
                   SECTION240.13d-l(b)(l}(ii)(E);

               (f) | |An employee benefit plan or endowment fund in accordance
                   with SECTION240.13d-l(b)(l}(ii)(F);

               (g) | |A parent holding company or control person in accordance
                   with SECTION240.13d-l(b)(l)(ii)(G);

               (h) | | A savings associations as defined in Section 3(b) of the
                   Federal Deposit Insurance Act (12 U.S.C. 1813);

               (i) | | A church plan that is excluded from the definition of an
                   investment company under section 3(c)(14) of the Investment
                   Company Act of 1940 (15 U.S.C. 80a-3);

               (j) | |A church plan that is excluded from the definition of an
                   investment company under section 3(c)(14) of the Investment
                   Company Act of 1940 (15 U.S.C. 80a-3);

               (j) | | Group, in accordance with SECTION240.13d-l(b)(l)(ii)(J).

ITEM 4. OWNERSHIP.

      Provide the following information regarding the aggregate number and
percentage of the class of securities of the issuer identified in Item 1.

               (a) Amount beneficially owned: 405,016

               (b) Percent of class: 1.08%

               (c) Number of shares as to which the person has:

                   (i)   Sole power to vote or to direct the vote 405,016

                   (ii)  Shared power to vote or to direct the vote ____.

                   (iii) Sole power to dispose or to direct the disposition of
                         405,016

                   (iv)  Shared power to dispose or to direct the disposition
                         of _____.


      Instruction. For computations regarding securities which represent a right
      to acquire an underlying security see Section N240.13d-3(d)(l).

ITEM 5. OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS

      If this statement is being filed to report the fact that as of the date
hereof the reporting person has ceased to be the beneficial owner of more than
five percent of the class of securities, check the following |X|.

                                       3


Instruction: Dissolution of a group requires a response to this item.

ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.

      If any other person is known to have the right to receive or the power to
direct the receipt of dividends from, or the proceeds from the sale of, such
securities, a statement to that effect should be included in response to this
item and, if such interest relates to more than five percent of the class, such
person should be identified. A listing of the shareholders of an investment
company registered under the Investment Company Act of 1940 or the beneficiaries
of employee benefit plan, pension fund or endowment fund is not required.

ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE
SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY

      If a parent holding company has filed this schedule, pursuant to Rule
13d-l(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the
identity and the Item 3 classification of the relevant subsidiary. If a parent
holding company has filed this schedule pursuant to Rule 13d-l(c) or Rule
13d-l(d), attach an exhibit stating the identification of the relevant
subsidiary.

ITEM 8. IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP

      If a group has filed this schedule pursuant to
SECTION240.13d-l(b)(l)(ii)(J), so indicate under Item 3(j) and attach an exhibit
stating the identity and Item 3 classification of each member of the group. If a
group has filed this schedule pursuant to SECTION240.13d-l(c) or
SECTION240.13d-I(d), attach an exhibit stating the identity of each member of
the group.

ITEM 9. NOTICE OF DISSOLUTION OF GROUP

      Notice of dissolution of a group may be furnished as an exhibit stating
the date of the dissolution and that all further filings with respect to
transactions in the security reported on will be filed, if required, by members
of the group, in their individual capacity. See Item 5.

ITEM 10. CERTIFICATION

        (a) The following certification shall be included if the statement is
filed pursuant to SECTION240.13d-1 (b):

               By signing below I certify that, to the best of
               my knowledge and belief, the securities referred
               to above were acquired and are held in the
               ordinary course of business and were not
               acquired and are not held for the purpose of or
               with the effect of changing or influencing the
               control of the issuer of the securities and were
               not acquired and are not held in connection with
               or as a participant in any transaction having
               that purpose or effect.

        (b)    The following certification shall be included if
               the statement is filed pursuant to
               SECTIONS240.13d-l(c): By signing below I certify
               that, to the best of my knowledge and belief,
               the securities referred to above were not
               acquired and are not held for the purpose of or
               with the effect of changing or influencing the
               control of the issuer of the securities and were
               not acquired and are not held in connection with
               or as a participant in any transaction having
               that purpose or effect.

                                       4

                                    SIGNATURE

      After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete, and
correct.




                                               January 25, 2010
                              ==================================================
                                                    Date

                                            /s/ Kevin M. Robinson
                              ==================================================
                                                  Signature

                                  Kevin M. Robinson, Senior Managing Director,
                                     General Counsel and Corporate Secretary
                                            Claymore Securities, Inc.
                              --------------------------------------------------
                                                  Name/Title

      The original statement shall be signed by each person on whose behalf the
statement is filed or his authorized representative. If the statement is signed
on behalf of a person by his authorized representative other than an executive
officer or general partner of the filing person, evidence of the
representative's authority to sign on behalf of such person shall be filed with
the statement, provided, however, that a power of attorney for this purpose
which is already on file with the Commission may be incorporated by reference.
The name and any title of each person who signs the statement shall be typed or
printed beneath his signature.

NOTE: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See SECTIONS240.13d-7 for other
parties for whom copies are to be sent.

ATTENTION: INTENTIONAL MISSTATEMENTS OR OMISSIONS OF FACT CONSTITUTE FEDERAL
CRIMINAL VIOLATIONS (SEE 18 U.S.C. 1001)

                                       5