OMB APPROVAL OMB Number:3235-0145 Expires:October 31, 1994 Estimated average burden hours per form 14.90 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. *) Sonus Pharmaceuticals, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) - -------------------------------------------------------------------------- 835692104 (CUSIP Number) Christopher J. Rupright, Esq. Shartsis Friese & Ginsburg One Maritime Plaza, 18th Floor San Francisco, CA 94111 (415) 421-6500 - --------------------------------------------------------------------------- (Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications) December 18, 1996 (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 Rule 13d-1(b)(3) or (4), check the following box / /. Check the following box if a fee is being paid with the statement / /. (A fee is not required only if the reporting person: (1) has a previous statement on file reporting beneficial ownership of more than five percent of the class of securities described in Item 1; and (2) has filed no amendment subsequent thereto reporting beneficial ownership of five percent or less of such class.) (See Rule 13d-7.) Note: Six copies of this statement, including all exhibits, should be filed with the Commission. See Rule 13d-1(a) for other parties to whom copies are to be sent. * 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 disclosures provided in a prior cover page. 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). SEC 1746 (12-91) SCHEDULE 13D CUSIP No. 835692104 Page 2 of 11 Pages - --------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON SS OR IRS IDENTIFICATION NO. OF ABOVE PERSON West Highland Capital, Inc. - --------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) / X / (b) / / - --------------------------------------------------------------------------- 3 SEC USE ONLY - --------------------------------------------------------------------------- 4 SOURCE OF FUNDS* AF - --------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(E) / / - --------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION California - --------------------------------------------------------------------------- NUMBER OF 7 SOLE VOTING POWER SHARES -0- BENEFICIALLY -------------------------------------------------- OWNED BY 8 SHARED VOTING POWER EACH 477,100 REPORTING -------------------------------------------------- PERSON 9 SOLE DISPOSITIVE POWER WITH -0- -------------------------------------------------- 10 SHARED DISPOSITIVE POWER 477,100 - --------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 477,100 - --------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES* / / - --------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.6 - --------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON* CO and IA - --------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! INCLUDE BOTH SIDES OF THE COVER PAGE, RESPONSES TO ITEMS 1-7 (INCLUDING EXHIBITS) OF THE SCHEDULE, AND THE SIGNATURE ATTESTATION. SCHEDULE 13D CUSIP No. 835692104 Page 3 of 11 Pages - --------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON SS OR IRS IDENTIFICATION NO. OF ABOVE PERSON Estero Partners, LLC - --------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) / X / (b) / / - --------------------------------------------------------------------------- 3 SEC USE ONLY - --------------------------------------------------------------------------- 4 SOURCE OF FUNDS* AF - --------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(E) / / - --------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION California - --------------------------------------------------------------------------- NUMBER OF 7 SOLE VOTING POWER SHARES -0- BENEFICIALLY -------------------------------------------------- OWNED BY 8 SHARED VOTING POWER EACH 398,050 REPORTING -------------------------------------------------- PERSON 9 SOLE DISPOSITIVE POWER WITH -0- -------------------------------------------------- 10 SHARED DISPOSITIVE POWER 398,050 - --------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 398,050 - --------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES* / / - --------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 4.7 - --------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON* OO - --------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! INCLUDE BOTH SIDES OF THE COVER PAGE, RESPONSES TO ITEMS 1-7 (INCLUDING EXHIBITS) OF THE SCHEDULE, AND THE SIGNATURE ATTESTATION. SCHEDULE 13D CUSIP No. 835692104 Page 4 of 11 Pages - --------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON SS OR IRS IDENTIFICATION NO. OF ABOVE PERSON Lang H. Gerhard - --------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) / X / (b) / / - --------------------------------------------------------------------------- 3 SEC USE ONLY - --------------------------------------------------------------------------- 4 SOURCE OF FUNDS* AF - --------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(E) / / - --------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION United States - --------------------------------------------------------------------------- NUMBER OF 7 SOLE VOTING POWER SHARES -0- BENEFICIALLY -------------------------------------------------- OWNED BY 8 SHARED VOTING POWER EACH 398,050 REPORTING -------------------------------------------------- PERSON 9 SOLE DISPOSITIVE POWER WITH -0- -------------------------------------------------- 10 SHARED DISPOSITIVE POWER 398,050 - --------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 398,050 - --------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES* / / - --------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 4.7 - --------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON* IN - --------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! INCLUDE BOTH SIDES OF THE COVER PAGE, RESPONSES TO ITEMS 1-7 (INCLUDING EXHIBITS) OF THE SCHEDULE, AND THE SIGNATURE ATTESTATION. SCHEDULE 13D CUSIP No. 835692104 Page 5 of 11 Pages - --------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON SS OR IRS IDENTIFICATION NO. OF ABOVE PERSON West Highland Partners, L.P. - --------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) / X / (b) / / - --------------------------------------------------------------------------- 3 SEC USE ONLY - --------------------------------------------------------------------------- 4 SOURCE OF FUNDS* WC - --------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(E) / / - --------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION California - --------------------------------------------------------------------------- NUMBER OF 7 SOLE VOTING POWER SHARES -0- BENEFICIALLY -------------------------------------------------- OWNED BY 8 SHARED VOTING POWER EACH 333,700 REPORTING -------------------------------------------------- PERSON 9 SOLE DISPOSITIVE POWER WITH -0- -------------------------------------------------- 10 SHARED DISPOSITIVE POWER 333,700 - --------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 333,700 - --------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES* / / - --------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 3.9 - --------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON* PN - --------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! INCLUDE BOTH SIDES OF THE COVER PAGE, RESPONSES TO ITEMS 1-7 (INCLUDING EXHIBITS) OF THE SCHEDULE, AND THE SIGNATURE ATTESTATION. SCHEDULE 13D CUSIP No. 835692104 Page 6 of 11 Pages - --------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON SS OR IRS IDENTIFICATION NO. OF ABOVE PERSON Buttonwood Partners, L.P. - --------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) / X / (b) / / - --------------------------------------------------------------------------- 3 SEC USE ONLY - --------------------------------------------------------------------------- 4 SOURCE OF FUNDS* WC - --------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(E) / / - --------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION California - --------------------------------------------------------------------------- NUMBER OF 7 SOLE VOTING POWER SHARES -0- BENEFICIALLY -------------------------------------------------- OWNED BY 8 SHARED VOTING POWER EACH 64,350 REPORTING -------------------------------------------------- PERSON 9 SOLE DISPOSITIVE POWER WITH -0- -------------------------------------------------- 10 SHARED DISPOSITIVE POWER 64,350 - --------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 64,350 - --------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES* / / - --------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.8 - --------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON* PN - --------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! INCLUDE BOTH SIDES OF THE COVER PAGE, RESPONSES TO ITEMS 1-7 (INCLUDING EXHIBITS) OF THE SCHEDULE, AND THE SIGNATURE ATTESTATION. SCHEDULE 13D CUSIP No. 835692104 Page 7 of 11 Pages ITEM 1. SECURITY AND ISSUER. This statement relates to shares of Common Stock (the "Stock") of Sonus Pharmaceuticals, Inc. ("SNUS"). The principal executive office of SNUS is located at 28026 20th Avenue, S.E., Suite 102, Bothell, WA 98021. ITEM 2. IDENTITY AND BACKGROUND. The persons filing this statement and the persons enumerated in Instruction C of Schedule 13D and, where applicable, their respective places of organization, general partners, directors, executive officers and controlling persons, and the information regarding them, is as follows: (a) Lang H. Gerhard ("Gerhard"); West Highland Capital, Inc., a California corporation ("WHC"); Estero Partners, LLC, a California limited liability company ("LLC"); West Highland Partners, L.P., a California limited partnership ("WHP"); Buttonwood Partners, L.P., a California limited partnership ("BP"). (b) The business address of Gerhard, WHC, LLC, WHP and BP is 300 Drake's Landing Road, Suite 290, Greenbrae, California 94904. (c) Gerhard is the sole director and occupies all the executive offices of WHC, which is an investment adviser. Gerhard is the sole manager of LLC. WHC, LLC and Gerhard are the general partners of WHP and BP, which are investment limited partnerships. (d) During the last five years, none of such persons has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors). (e) During the last five years, none of such persons was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws. (f) Gerhard is a citizen of the United States of America. SCHEDULE 13D CUSIP No. 835692104 Page 8 of 11 Pages ITEM 3. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION. The source and amount of funds used in purchasing the Stock were as follows: Purchaser Source of Funds Amount WHC Funds Under Management(1) $5,569,163.00 WHP Working Capital $3,757,386.64 BP Working Capital $ 726,311.22 (1) Includes funds invested by WHP and BP in Stock. ITEM 4. PURPOSE OF TRANSACTION. The sole purpose of the acquisitions of the Stock reported herein was and is for investment. ITEM 5. INTEREST IN SECURITIES OF THE ISSUER. The beneficial ownership of the Stock of the persons named in Item 2 of this statement is as follows at the date hereof: Aggregate Beneficially Owned Voting Power Dispositive Power Name Number Percent Sole Shared Sole Shared Gerhard 398,050 4.7 -0- 398,050 -0- 398,050 WHC 477,100 5.6 -0- 477,100 -0- 477,100 LLC 398,050 4.7 -0- 398,050 -0- 398,050 WHP 333,700 3.9 -0- 333,700 -0- 333,700 BP 64,350 0.8 -0- 64,350 -0- 64,350 SCHEDULE 13D CUSIP No. 835692104 Page 9 of 11 Pages The persons filing this statement effected the following transactions in the Stock on the dates indicated, and such transactions are the only transactions by the persons filing this statement in the Stock since October 19, 1996: Purchase Number Price Broker Name or Sale Date of Shares Per Share Used WHP P 12-16-96 6,800 22.5000 INST BP P 12-16-96 1,400 22.5000 INST WHC P 12-16-96 1,800 22.5000 INST WHP P 12-17-96 13,600 22.6875 HMQT BP P 12-17-96 2,800 22.6875 HMQT WHC P 12-17-96 3,600 22.6875 HMQT WHP P 12-18-96 23,800 24.1428 HMQT BP P 12-18-96 4,900 24.1428 HMQT WHC P 12-18-96 6,300 24.1428 HMQT WHP P 12-26-96 5,000 28.1250 HMQT HMQT - Hambrecht & Quist Incorporated INST - Instinet Corporation SCHEDULE 13D CUSIP No. 835692104 Page 10 of 11 Pages ITEM. 6. CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT TO SECURITIES OF THE ISSUER. Gerhard, WHC and LLC are the general partners of WHP and BP pursuant to limited partnership agreements providing to Gerhard, WHC and LLC the authority, among other things, to invest the funds of WHP and BP in Stock, to vote and dispose of stock and to file this statement on behalf of WHP and BP. Pursuant to such limited partnership agreements, the general partners of WHP and BP are entitled to allocations based on assets under management and realized and unrealized gains, if certain conditions are met. Pursuant to investment management agreements, WHC is authorized, among other things, to invest funds of its various investment advisory clients, and to vote and dispose of those securities. Such investment management agreements may be terminated by either party on notice as provided in such agreements and provide for fees payable to WHC based on assets under management and realized and unrealized gains. ITEM 7. MATERIAL TO BE FILED AS EXHIBITS. A. Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G (including power of attorney). SIGNATURES After reasonable inquiry and to the best of my knowledge, I certify that the information set forth in this statement is true, complete and correct. DATED: December 30, 1996. /s/ Lang H. Gerhard WEST HIGHLAND PARTNERS, L.P. Lang H. Gerhard WEST HIGHLAND CAPITAL, INC. By: /s/ Lang H. Gerhard Lang H. Gerhard, General Partner By: /s/ Lang H. Gerhard Lang H. Gerhard, President BUTTONWOOD PARTNERS, L.P. ESTERO PARTNERS, LLC By: /s/ Lang H. Gerhard Lang H. Gerhard, General Partner By: /s/ Lang H. Gerhard Lang H. Gerhard, Manager SCHEDULE 13D CUSIP No. 835692104 Page 11 of 11 Pages EXHIBIT A AGREEMENT REGARDING JOINT FILING OF STATEMENT ON SCHEDULE 13D OR 13G The undersigned agree to file jointly with the Securities and Exchange Commission (the "SEC") any and all statements on Schedule 13D or Schedule 13G (and any amendments or supplements thereto) required under section 13(d) of the Securities Exchange Act of 1934, as amended, in connection with purchases by the undersigned of securities of Sonus Pharmaceuticals, Inc. For that purpose, the undersigned hereby constitute and appoint West Highland Capital, Inc., a California corporation, as their true and lawful agent and attorney- in-fact, with full power and authority for and on behalf of the undersigned to prepare or cause to be prepared, sign, file with the SEC and furnish to any other person all certificates, instruments, agreements and documents necessary to comply with section 13(d) and section 16(a) of the Securities Exchange Act of 1934, as amended, in connection with said purchases, and to do and perform every act necessary and proper to be done incident to the exercise of the foregoing power, as fully as the undersigned might or could do if personally present. DATED: December 30, 1996. /s/ Lang H. Gerhard WEST HIGHLAND PARTNERS, L.P. Lang H. Gerhard WEST HIGHLAND CAPITAL, INC. By: /s/ Lang H. Gerhard Lang H. Gerhard, General Partner By: /s/ Lang H. Gerhard Lang H. Gerhard, President BUTTONWOOD PARTNERS, L.P. ESTERO PARTNERS, LLC By: /s/ Lang H. Gerhard Lang H. Gerhard, General Partner By: /s/ Lang H. Gerhard Lang H. Gerhard, Manager C:\DMS\9000\001\0193462.WP