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+--------+
| FORM 4 |                       U.S. SECURITIES AND EXCHANGE COMMISSION
+--------+                               WASHINGTON, D.C. 20549

[_] Check this box if
    no longer subject         STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP
    to Section 16.
    Form 4 or Form 5       Filed pursuant to Section 16(a) of the Securities
    obligations may           Exchange Act of 1934, Section 17(a) of the
    continue. See            Public Utility Holding Company Act of 1935 or
    Instruction 1(b).      Section 30(f) of the Investment Company Act of 1940

(Print or Type Responses)

- --------------------------------------------------------------------------------
1.  Name and Address of Reporting Person*

         Naso                        Robert                            B.
- --------------------------------------------------------------------------------
        (Last)                      (First)                        (Middle)

8360 Lochaven Drive
- --------------------------------------------------------------------------------
                                   (Street)

     Gaithersburg                     MD                              20882
- --------------------------------------------------------------------------------
        (City)                      (State)                           (Zip)


2.  Issuer Name and Ticker or Trading Symbol   Nabi (NABI)
                                             -----------------------------------

3.  IRS or Identification Number of Reporting Person if an entity
    (Voluntary)
                --------------

4.  Statement for Month/Year           March 2000
                             ---------------------------------------------------

5.  If Amendment, Date of Original (Month/Year)     March 30, 2000
                                               ---------------------------------


6.  Relationship of Reporting Person(s) to Issuer (Check all applicable)


    [_] Director    [X] Officer              [_] 10% Owner    [_] Other
                        (give title below)                       (specify below)

                Senior Vice President, Manufacturing Operations
                -----------------------------------------------

7.  Individual or Joint/Group Filing (Check Applicable Line)

      X
    ____ Form filed by One Reporting Person

    ____ Form filed by More than One Reporting Person

TABLE I--NON-DERIVATIVE SECURITIES ACQUIRED, DISPOSED OF, OR BENEFICIALLY OWNED

- ------------------------------------------------------------------------------------------------------------------------------------ 1. Title 2. Trans- 3. Trans- 4. Securities Acquired (A) 5. Amount of 6. Owner- 7. Nature of action action or Disposed of (D) Securities ship of In- Security Date Code (Instr. 3, 4 and 5) Beneficially Form: direct (Instr. 3) (Month/ (Instr. 8) Owned at Direct Bene- Day/ ----------------------------------------------- End of (D) or ficial Year) Month Indirect Owner- Code V Amount (A) or Price (Instr. 3 and 4) (I) ship (D) (Instr. 4) (Instr. 4) - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ Common Stock 3-2-00 M 17,500 A $2.69 D -- - ------------------------------------------------------------------------------------------------------------------------------------ Common Stock 3-2-00 S (1) 11,500 D $10.049 - ------------------------------------------------------------------------------------------------------------------------------------ Common Stock 3-2-00 S 5,000 D $10.375 1,000 D -- - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. * If this form is filed by more than one reporting person, see Instruction 4(b)(v). FORM 4 (continued) TABLE II--DERIVATIVE SECURITIES ACQUIRED, DISPOSED OF, OR BENEFICIALLY OWNED (e.g., puts, calls, warrants, options, convertible securities)
- ----------------------------------------------------------------------------------------------------------------------------- 1. Title of Derivative 2. Conver- 3. Trans- 4. Transac- 5. Number of Deriv- Security (Instr. 3) sion or action tion Code ative Securities Exercise Date (Instr. 8) Acquired (A) or Price of (Month/ Disposed of (D) Deriv- Day/ (Instr. 3, 4, and 5) ative Year) Security --------------------------------------------------- Code V (A) (D) - ----------------------------------------------------------------------------------------------------------------------------- - ----------------------------------------------------------------------------------------------------------------------------- Options (Right to Buy) $7.0625 2-7-00 A V 1 - ----------------------------------------------------------------------------------------------------------------------------- Options (Right to Buy) $2.69 3-2-00 M 1* - ----------------------------------------------------------------------------------------------------------------------------- Options - ----------------------------------------------------------------------------------------------------------------------------- - ----------------------------------------------------------------------------------------------------------------------------- - -----------------------------------------------------------------------------------------------------------------------------
TABLE II--DERIVATIVE SECURITIES ACQUIRED, DISPOSED OF, OR BENEFICIALLY OWNED (e.g., puts, calls, warrants, options, convertible securities)--CONTINUED
- ------------------------------------------------------------------------------------------------------------------------------------ 6. Date Exer- 7. Title and Amount of 8. Price 9. Number 10. Owner- 11. Na- cisable and Underlying Securities of of Deriv- ship ture Expiration (Instr. 3 and 4) Deriv- ative Form of In- Date ative Secur- of De- direct (Month/Day/ Secur- ities rivative Bene- Year) ity Bene- Secu- ficial (Instr. ficially rity: Owner- -------------------------------------------- 5) Owned Direct ship Date Expira- Amount or at End (D) or (Instr. Exer- tion Title Number of of Indi- 4) cisable Date Shares Month rect (1) (Instr. 4) (Instr. 4) - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ Common (2) 2-7-10 Stock 58,811 -- -- D -- - ------------------------------------------------------------------------------------------------------------------------------------ Common (3) 2-1-09 Stock 17,500 -- -- D -- - ------------------------------------------------------------------------------------------------------------------------------------ Common Stock 334,052 -- 9 D -- - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------
Explanation of Responses: (1) Includes securities sold to cover cashless exercise of option. (2) Option granted under the 1990 Equity Incentive Plan that becomes exercisable with respect to 25% of the shares issuable thereunder on each of February 7, 2001, 2002, 2003 and 2004. (3) Option granted 2-1-99 under the 1990 Equity Incentive Plan that becomes exercisable with respect to 25% of the underlying shares of Common Stock on each of the first four anniversaries of the date of grant. *Partial disposition. **Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a). Note: File three copies of this Form, one of which must be manually signed. If space provided is insufficient, see Instruction 6 for procedure. Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number. /s/ Robert B. Naso 4-13-00 ------------------------------- ----------------- **Signature of Reporting Person Date