Filed by Valero Energy Corporation
                         Pursuant to Rule 425 under the Securities Act of 1933
                                      and deemed filed pursuant to Rule 14a-12
                                     under the Securities Exchange Act of 1934
                                   Subject Company:  Valero Energy Corporation
                                                    Registration No. 333-61756




The following information was posted to Valero Energy Corporation's web site on
July 26, 2001:



-----------------        =======================================================
VALERO/UDS               VALERO/UDS DEAL PRICING MECHANISM
                         -------------------------------------------------------

        o In May, 2001 Valero Energy and Ultramar Diamond Shamrock agreed to a
          part-cash/part-stock  merger in which Valero would exchange all of the
          shares  of UDS for  consideration  with a value  representing  a 31.3%
          premium to UDS' stock price, based on the average closing price of UDS
          for the 10 day period prior to April 26th.

        o The  total  consideration  equates  to  $27.50  in cash  and a fixed
          exchange  ratio of 0.614 Valero shares for each  outstanding  share of
          UDS  common  stock,   representing  an  aggregate   consideration   of
          approximately  $2  billion  in cash plus  approximately  44.4  million
          Valero shares (subject to possible adjustment as described below).

        o A UDS stockholder can elect to receive  consideration in the form of
          cash, Valero stock or a combination.  Whatever the form, the mechanism
          is designed such that the per-share  consideration  will have the same
          value,  based on the average  price of Valero common stock during a 10
          day measurement period ending 3 days before closing, regardless of the
          form of consideration.  That per-share value, whether paid in the form
          of stock or cash,  will be the sum of (a) $27.50  and (b) the  average
          value of 0.614 Valero shares during the measurement period.

        o The elections  will be subject to proration,  as the total number of
          Valero  shares to be issued and the total amount of cash to be paid in
          the merger to UDS  stockholders  as a group are each fixed except that
          Valero may add more stock,  valued at the measurement period value and
          in lieu of an  equivalent  amount of cash,  if needed to maintain  the
          tax-free treatment of the merger. If stock is oversubscribed, then UDS
          stockholders who have elected stock will nevertheless receive cash for
          some of their UDS shares,  on a pro rata basis, and vice versa if cash
          is oversubscribed. Also, if based on the average price of Valero stock
          during  the  measurement  period  the limit on the  percentage  of UDS
          shares that may be  converted to stock  consideration  is greater than
          50%, Valero at its option,  may reduce that limit to 50%.






-----------------      =========================================================
VALERO/UDS             EQUALIZATION MECHANISM
                       MM,EXCEPT PER SHARE FIGURES
                       ---------------------------------------------------------



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

                       TRANSACTION STRUCTURE

                       -----------------------------------------------------------------------------------------------------------
                                                                                                                     
                       Total UDS Shares                                   72.3
                       -------------------------------------------------------------------------------------------------------------
                       CASH PORTION (VALUE OF $55.00 OFFER AT 50%)                STOCK PORTION (VALUE OF 1.228X OFFER AT 50%)
                       -------------------------------------------------------------------------------------------------------------
                       Cash Offer per Share                               $27.50  Stock Exchange Ratio                        0.614x
                       -------------------------------------------------------------------------------------------------------------
                       Cash Offered in Transaction ($27.50 x 72.3 Shares) $1,988  Number of Valero Shares (0.614 x 72.3 Shares) 44.4
                       -------------------------------------------------------------------------------------------------------------

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





                                                                                    
------------------------------------------------------------------------------------------------------------------------------------
                                                      TOTAL                      PERCENT         PERCENT    SHARES
                         STOCK  BLENDED      TOTAL    VALUE       TOTAL          OF UDS  TOTAL   OF UDS     ISSUED      CASH REDUCED
VALERO  CASH   EXCHANGE  VALUE  TRANSACTION  CASH     OF STOCK    CONSIDERATION  SHARES  SHARES  SHARES     TO MAINTAIN BY ISSUING
SHARE   VALUE  RATIO     AT     VALUE PER    OFFERED  OFFERED BY  OFFERED BY     PURCH.  OFFERED PURCHASED  43% DEAL    ADDITIONAL
PRICE   AT 50% AT 50%    50%    UDS SHARE    BY       VALERO      VALERO         CASH    BY      FOR VALERO VALUE IN    SHARES
                                             VALERO                                      VALERO  STOCK      STOCK
------------------------------------------------------------------------------------------------------------------------------------
$25.00  $27.50 0.614x    $15.35 [$42.85]     $1,766   $1,332      $3,098         57.0%   53.3    43.0%      8.9         $222.4
------------------------------------------------------------------------------------------------------------------------------------
 30.00   27.50 0.614x     18.42 [45.92 ]      1,892    1,428       3,320         57.0%   47.6    43.0%      3.2           95.8
------------------------------------------------------------------------------------------------------------------------------------
 33.73*  27.50 0.614x     20.71 [48.21]       1,988    1,498       3,486         57.0%   44.4    43.0%      --            --
------------------------------------------------------------------------------------------------------------------------------------
 35.00   27.50 0.614x     21.49 [48.99]       1,988    1,554       3,542         56.1%   44.4    43.9%      --            --
------------------------------------------------------------------------------------------------------------------------------------
 40.00   27.50 0.614x     24.56 [52.06]       1,988    1,776       3,764         52.8%   44.4    47.2%      --            --
------------------------------------------------------------------------------------------------------------------------------------
 45.00   27.50 0.614x     27.63 [55.13]       1,988    1,998       3,986         49.9%   44.4    50.1%      --            --
------------------------------------------------------------------------------------------------------------------------------------
 50.00   27.50 0.614x     30.70 [58.20]       1,988    2,220       4,208         47.3%   44.4    52.7%      --            --
------------------------------------------------------------------------------------------------------------------------------------
  A       B      C         D      E            F        G           H              I       J       K          L           M
------------------------------------------------------------------------------------------------------------------------------------
                         =AxC   =B+D         =$1,988-M =AxJ       =F+G           =F/H    =44.4+L =G/H                   =LxA
------------------------------------------------------------------------------------------------------------------------------------




NOTES:
o Assumes at least 43% of the consideration will be required to be paid in
  Valero stock in order to maination the tax free status of the transaction with
  respect to the stock consideration. Pursuant to the terms of the merger
  agreement, the minimum percentage required to be paid in stock will not be
  determinded until closing and may be higher or lower than the assumption made
  for this example.
o $33.73 represents the breakeven price below which additional stock may be
  issued to preserve tax-free treatment.






-----------------        =======================================================
VALERO/UDS               VALERO/UDS DEAL PRICING MECHANISM
                         -------------------------------------------------------


          STATEMENTS CONTAINED IN THIS PRESS RELEASE THAT STATE THE COMPANY'S OR
          MANAGEMENT'S   EXPECTATIONS   OR   PREDICTIONS   OF  THE   FUTURE  ARE
          FORWARD-LOOKING  STATEMENTS  INTENDED TO BE COVERED BY THE SAFE HARBOR
          PROVISIONS OF THE SECURITIES  ACT OF 1933 AND THE SECURITIES  EXCHANGE
          ACT OF 1934. IT IS IMPORTANT TO NOTE THAT THE COMPANY'S ACTUAL RESULTS
          COULD DIFFER  MATERIALLY FROM THOSE PROJECTED IN SUCH  FORWARD-LOOKING
          STATEMENTS.


          INVESTORS  AND  SECURITY  HOLDERS  ARE URGED TO READ THE  JOINT  PROXY
          STATEMENT/PROSPECTUS  THAT WILL BE SENT TO VALERO AND UDS STOCKHOLDERS
          REGARDING THE PROPOSED MERGER,  WHEN IT BECOMES AVAILABLE,  BECAUSE IT
          WILL    CONTAIN    IMPORTANT    INFORMATION.     THE    JOINT    PROXY
          STATEMENT/PROSPECTUS  WILL BE FILED WITH THE  SECURITIES  AND EXCHANGE
          COMMISSION  BY VALERO AND UDS.  INVESTORS  AND  SECURITY  HOLDERS  MAY
          OBTAIN A FREE COPY OF THE JOINT PROXY STATEMENT/PROSPECTUS, WHEN IT IS
          AVAILABLE,  AND  OTHER  DOCUMENTS  FILED  BY  VALERO  AND UDS WITH THE
          COMMISSION  AT THE  COMMISSION'S  WEB SITE AT  WWW.SEC.GOV.  THE JOINT
          PROXY  STATEMENT/PROSPECTUS  AND  THESE  OTHER  DOCUMENTS  MAY ALSO BE
          OBTAINED,  WHEN  AVAILABLE,  FREE  OF  CHARGE  FROM  VALERO  AND  UDS.
          STOCKHOLDERS     SHOULD    READ    THE    DEFINITIVE    JOINT    PROXY
          STATEMENT/PROSPECTUS CAREFULLY BEFORE MAKING A DECISION CONCERNING THE
          MERGER.

          VALERO AND UDS, AND THEIR RESPECTIVE DIRECTORS, EXECUTIVE OFFICERS AND
          CERTAIN OTHER OF THEIR RESPECTIVE EMPLOYEES, MAY BE SOLICITING PROXIES
          FROM THEIR  RESPECTIVE  STOCKHOLDERS  IN FAVOR OF THE  APPROVAL OF THE
          MERGER. INFORMATION REGARDING THE PERSONS WHO MAY, UNDER SEC RULES, BE
          DEEMED  TO BE  PARTICIPANTS  IN THE  SOLICITATION  OF  VALERO  AND UDS
          STOCKHOLDERS  IN CONNECTION  WITH THE MERGER IS SET FORTH, IN THE CASE
          OF VALERO,  IN VALERO'S PROXY  STATEMENT FOR ITS 2001 ANNUAL  MEETING,
          FILED WITH THE SEC ON MARCH 28, 2001, AND IN THE CASE OF UDS, IN UDS'S
          PROXY  STATEMENT  FOR ITS 2001 ANNUAL  MEETING,  FILED WITH THE SEC ON
          MARCH 27, 2001,  AND ADDITIONAL  INFORMATION  WILL BE SET FORTH IN THE
          DEFINITIVE  PROXY  STATEMENT/PROSPECTUS  REFERRED  TO ABOVE WHEN IT IS
          FILED WITH THE SEC.