PROSPECTUS SUPPLEMENT                                         File No. 333-52822
- ---------------------                                             Rule 424(b)(3)
(To Prospectus Supplement and Prospectus
dated January 24, 2001)
Prospectus number:      2105


                             Merrill Lynch & Co., Inc.
                           Medium Term Notes, Series B
                   Due Nine Months or More from Date of Issue


                                Fixed Rate Notes


Principal Amount:  $75,000,000        Original Issue Date:    March 16, 2001

CUSIP Number:      59018Y GU9         Stated Maturity Date:   April 12, 2002


Day Count Convention:
- ---------------------
[X]  Actual/360

[ ]  30/360

[ ]  Actual/Actual


Interest Rate Basis:
- --------------------
[ ]  LIBOR                             [ ]  Commercial Paper Rate

[ ]  CMT Rate                          [ ]  Eleventh District Cost of Funds Rate

[ ]  Prime Rate                        [ ]  CD Rate

[ ]  Federal Funds Rate                [ ]  Other (see attached)

[ ]  Treasury Rate


   Designated CMT Page:                Designated LIBOR Page:
        CMT Telerate Page:                  LIBOR Telerate Page:
        CMT Reuters Page:                   LIBOR Reuters Page:


Index Maturity:          Not Applicable    Minimum Interest Rate: Not Applicable

Spread:                  Not Applicable    Maximum Interest Rate: Not Applicable

Initial Interest Rate:   4.80000%          Spread Multiplier:     Not Applicable


Interest Payment Dates:    At Maturity


Repayment at the
Option of the Holder:      The Notes cannot be repaid prior to the Stated
                           Maturity Date.

Redemption at the
Option of the Company:     The Notes cannot be redeemed prior to the Stated
                           Maturity Date.

Form:                      The Notes are being issued in fully registered
                           book-entry form.

Trustee:                   The Chase Manhattan Bank

Dated:                     March 13, 2001