UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No ) VICOR CORPORATION (Name of Issuer) COMMON STOCK (Title of Class of Securities) 925815102 (CUSIP Number) 1. NAME OF REPORTING PERSON Nevis Capital Management, Inc SS OR IRS IDENTIFICATION NO. OF ABOVE PERSON 52-1740975 2. CHECK THE APPROPRIATE LETTTER IF A MEMBER OF A GROUP: (a) (b) 4. CITIZENSHIP OR PLACE OF ORGANIZATION Maryland 5. SOLE VOTING POWER: 3,148,444 6. SHARED VOTING POWER: 0 7. SOLE DISPOSITIVE POWER: 3,148,444 8. SHARED DISPOSITIVE POWER: 0 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 3,148,444 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES: 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9: 10.6% 12. TYPE OF REPORTING PERSON: IA ITEM 1. (a) Name of Issuer: VICOR CORPORATION (b) Address of Issuer's Principal Executive Offices: 23 FRONTAGE RD, ANDOVER MA 01810 ITEM 2. (a) Name of Person Filing: NEVIS CAPITAL MANAGEMENT, INC. (b) Address of Principal Business Office: 1119 ST PAUL ST, BALTIMORE MD 21202 (c) Citizenship: MARYLAND (d) Title of Class of Securities: COMMON STOCK (e) CUSIP Number: 925815102 ITEM 3. If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b), check whether the person filing is a: (e) Investment Advisor registered under Section 203 of the Investment Advisors Act of 1940. X ITEM 4. Ownership (a) Amount Beneficially Owned: 3,148,444 (b) Percent of Class: 10.6% (c) Number of shares as to which such person has (i) sole power to vote or to direct vote: 3,148,444 (ii) shared power to vote or to direct the vote: 0 (iii) sole power to dispose or to direct the disposition: 3,148,444 (iv) shared power to dispose or to direct the disposition: 0 Signature, David R. Wilmerding, III - President February 2, 1999