EXHIBIT 99.1

  Ariba Acquires TradingDynamics, Inc. Acquisition Opens New Markets, Adds New
        Network Services, and Accelerates the Growth of the Ariba Network

NET MARKET MAKERS CONFERENCE - BERKELEY, Calif. -November 15, 1999 - Ariba, Inc.
today announced that it has signed a definitive agreement to acquire
TradingDynamics, Inc., a leading provider of business-to-business Internet
trading applications. With this acquisition, Ariba expands its market by adding
eCommerce products and services designed for Net Market Makers to create
Internet business-to-business exchanges. In addition, new value-added network
services will be offered through the Ariba Network(TM) marketplace platform to
Ariba customers and suppliers. These new services will include auction, request
for quote (RFQ), reverse auction, and exchange mechanisms. This acquisition
reflects Ariba's strategy to lead the electronic trade revolution by building a
global technical and business infrastructure that enables buyers, suppliers, and
other providers to reduce costs, increase revenue, and build competitive
advantage on the Internet.

The agreement is structured as a stock for stock merger, and will be accounted
for as a purchase transaction. Ariba will issue stock worth approximately $400
million, based on current trading ranges, to TradingDynamics stockholders. The
parties expect that the transaction will close in calendar Q1, 2000.

Keith Krach, Ariba president and CEO, said, "This acquisition is the latest step
in our business strategy to drive the adoption of business-to-business eCommerce
by adding value to the Ariba network platform. These new markets and network
services will help make the global economy more efficient by enabling market
makers to deliver frictionless commerce environments in which market forces will
dynamically match business supply and demand."

Ariba is the market leader in business-to-business electronic commerce, with a
global buyer base exceeding an aggregate buying power of $140 billion. Ariba
buy-side customers include Andersen Consulting, Bristol-Myers Squibb, Chevron,
Cisco, Dow Chemical, Federal Express, Hewlett-Packard, MCI Worldcom, Merck,
Motorola, SAirGroup, Transamerica, and Visa. In addition, today there are more
than 20,000 supply-side customers already participating in the Ariba Network
platform.

TradingDynamics has delivered a family of applications designed to meet the
needs of business-to-business commerce. Applications currently include auction,
reverse auction, and exchange. Founded in 1998, the company currently has six
customers, including eLow, PlasticsNet, and SkillsVillage.

Krach added, "We partnered with TradingDynamics because they demonstrated clear
leadership in three areas. Their team of economists, computer scientists and
experienced managers is unmatched. They have developed a next generation
product, which they delivered on time. And,




early Net Market Makers have already embraced their solution. We believe we have
a winning partnership on our hands."

Kirk Cruikshank, TradingDynamics president and CEO, said, "The demand for
business-to-business applications is exploding. At the same time, customers want
broad, configurable, modular solutions that address all aspects of eCommerce -
from buy-side to sell-side, and from fixed to dynamic pricing. We believe that
Ariba's unified global network platform is the best approach. We went with the
leader."

New Market: Net Market Makers
Keith Krach said, "We are committed to partnering with Net Market Makers to
enable new business-to-business exchanges. We made our first move into this
market in September, when we announced the Ariba Internet Business Exchange(TM)
(Ariba IBX(TM)) service. Today's announcement not only significantly broadens
our solution offering with new services, but also adds expertise and an
organization focused on this important customer base."

Net Market Makers are companies that bring together fragmented groups of buyers
and sellers online for greater buying power and larger markets in both vertical
and horizontal industries. For example, an airline could build a vertical market
around buyers, suppliers, and goods and services associated with travel and
transportation while a financial institution could build a horizontal
marketplace by inviting its customers and suppliers of all kinds to participate
in an Internet-based commerce community. Analyst groups predict strong growth in
this area, with Gartner Group predicting 7,500 to 10,000 new Net Markets
established by 2002.

TradingDynamics has targeted its business-to-business trading product suite
specifically at this market. Additionally, the Ariba IBX service is a hosted
Internet service designed for Net Market Makers. IBX enables a full range of Net
Market Makers to quickly build exchanges and commerce communities using the
infrastructure of the Ariba Network -- without being required to purchase,
install, build and maintain their own separate network infrastructures and
applications.

Now Ariba, with TradingDynamics, will offer Net Market Makers even more. Ariba
believes that it will provide the industry's most configurable, comprehensive,
modular business-to-business eCommerce platform, giving Net Market Makers
unprecedented choice, flexibility and control. Net Market Makers can take
advantage of the Ariba Network infrastructure, accelerating transaction volumes
through access to Ariba's existing and growing buyer community and creating new
revenue opportunities through products from affiliate suppliers.

New Network Services for Existing Customers
Ariba will now offer new dynamic pricing services to current and future
customers. Keenan Vision estimates that approximately 39 percent of
business-to-business Internet commerce will be conducted using dynamic pricing
mechanisms, predicting that by 2004, business-to-business Internet commerce will
reach $1.1 trillion in the United States, and $439 billion of that will be
conducted using dynamic pricing mechanisms.




With the TradingDynamics application services, Ariba will offer its customers
new sourcing mechanisms for non-contract items, allowing them to use a single
solution for both contract-based and ad hoc efforts. The new services will
include reverse auction and RFQ. Through access to Net Market Makers, buyers can
now also address the entire supply chain, from indirect to direct materials.
Suppliers will now be able to use auction and exchange services to optimize
prices for scarce goods and to distribute excess inventory.

Integration Plans
Upon closing of the transaction, Ariba will merge TradingDynamics into its
operations and retain all employees. TradingDynamics is currently located less
than two miles from Ariba corporate headquarters. The company will continue
TradingDynamics' focus on Net Market Makers, supporting its strategic thrust
with aggressive investment and resources. Kirk Cruikshank, the company's
president and CEO, will report to Keith Krach.

The company plans to aggressively market the TradingDynamics applications and
services available today. Integration of the TradingDynamics applications and
services into the Ariba Network platform will begin immediately after closing,
starting with incorporating cXML (Commerce XML), the leading standard for
business-to-business eCommerce on the Internet, into TradingDynamics products.
Ariba will deliver TradingDynamics services hosted on the Ariba Network in Q1,
2000.

About TradingDynamics
TradingDynamics is a leading provider of business-to-business Internet trading
applications. Combining expertise in economics, market design and Internet
application development, the company lets net market makers and corporations
quickly deploy and configure a range of dynamically-priced markets - including
auctions, reverse auctions and exchanges. The company was founded in May 1998,
employs approximately 50 people, and received funding from Atlas Ventures and
New Enterprise Associates. The TradingDynamics product suite has been generally
available since October 1999. For more information on TradingDynamics, please
see www.tradingdynamics.com.

About Ariba
Ariba, Inc. is the world's leader in business-to-business electronic commerce
services and software. The company provides the Ariba Network platform, the
industry's leading open, unified global platform for business-to-business
commerce on the Internet. Ariba's software and services leverage the Ariba
Network platform to automate and integrate the internal and external commerce
processes of buyers, suppliers, and value-added service providers, delivering a
global eCommerce infrastructure that provides cost saving and revenue
opportunities for businesses of all sizes. Ariba can be contacted in the U.S. at
+1-650-930-6200 or at www.ariba.com.

Ariba will be holding an analyst/press briefing conference call at 5:30 p.m.
EST/2:30 p.m. PST today. To participate in the call, please dial: 719/457-2626.

Information in this release that involves Ariba's expectations, beliefs, hopes,
plans, intentions or strategies regarding the future are forward-looking
statements that involve risks and




uncertainties. All forward-looking statements included in this release are based
upon information available to Ariba as of the date of the release, and we assume
no obligation to update any such forward-looking statement. These statements are
not guarantees of future performance and actual results could differ materially
from our current expectations. Factors that could cause or contribute to such
differences include, but are not limited to, delays in development or shipment
of the TradingDynamics product suite, new versions of our ORMS application or of
our Ariba Network; lack of market acceptance of the TradingDynamics product
suite or the Ariba Network or other new products or services; inability to
continue to develop competitive new products and services on a timely basis;
introduction of new products or services by major competitors; and our ability
to attract and retain qualified employees, including those of TradingDynamics.
These and other factors and risks associated with our business are discussed in
the Company's registration statement on Form S-1 declared effective by the
Securities and Exchange Commission ("SEC") on June 22, 1999, and in the
Company's Form 10-Q filed August 16, 1999.

Ariba and the Ariba logo are registered trademarks of Ariba, Inc. Ariba Network,
Ariba ORMS, and AribaLive are trademarks of Ariba, Inc. All other products or
company names mentioned are used for identification purposes only, and may be
trademarks of their respective owners.