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                                                                   EXHIBIT 99.1


ARBOR SOFTWARE AND HYPERION SOFTWARE MERGE TO CREATE
ANALYTIC APPLICATIONS MARKETPLACE LEADER

SUNNYVALE, CA and STAMFORD, CT, May 26, 1998 - Arbor Software Corporation
(Nasdaq: ARSW) and Hyperion Software Corporation (Nasdaq: HYSW) today announced
a strategic business combination that will create a global leader in the rapidly
emerging analytic applications marketplace. The Boards of Directors of both
companies have unanimously approved a definitive agreement to merge the two
organizations. The combined company will operate under the name Hyperion
Solutions Corporation and will have its headquarters in Sunnyvale, California.

The combination will create a global company with more than $350 million in
revenues based on pro forma results for the twelve months ended March 31, 1998,
more than 1,800 employees operating in 26 countries, leading positions in each
of its core markets and a customer list that includes two thirds of the Fortune
100. The combined company will be able to provide customers worldwide with
comprehensive analytic applications solutions. Research firm International Data
Corporation (IDC) estimates that the analytic applications marketplace will grow
from over $800 million in 1997 to exceed $2.6 billion by the year 2001.

The merger will be effected by the issuance of 0.95 shares of Arbor Software
Corporation common stock for each share of Hyperion Software Corporation common
stock. Concurrent with the exchange, the continuing company will be renamed
Hyperion Solutions Corporation. The transaction will be accounted for as a
pooling of interests, and based on the closing Nasdaq prices on Friday, May 22,
the combined company's market capitalization would be valued at approximately
$1.3 billion. Arbor shareholders will own approximately 40 percent of the
continuing company while Hyperion shareholders will own approximately 60
percent. Subject to regulatory approvals and approval of each company's
shareholders, and other customary closing conditions, the transaction is
expected to close late this summer.

John Dillon, Arbor's current chairman and CEO, will become CEO of the combined
company and Jim Perakis, Hyperion's current chairman and CEO, will become
chairman of the combined company. Stephen Imbler, Arbor's current CFO, Bill
Binch, Arbor's current head of sales, Kirk Cruikshank, Arbor's current head of
marketing, Craig Schiff, Hyperion's current head of services and Mark Bilger,
Hyperion's current head of development, will hold these positions in the
combined company. The Board of Directors of the merged organization will include
four directors from Hyperion and three directors from Arbor.

"We are very excited about the opportunity to lead the analytic applications
marketplace as an open, best-in-class provider of custom, on-demand and packaged
analytic applications that leverage the power of OLAP technology," said John
Dillon, chairman and CEO of Arbor. "The combination with Hyperion offers us the
opportunity to address a broader set of customer needs, increase value for our
shareholders, and provide even greater career opportunities for our employees."

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"The merger of Arbor and Hyperion is intended to allow us to broaden the
delivery of analytic application solutions to customers worldwide," said Jim
Perakis, chairman and CEO of Hyperion. "We are all very enthusiastic about the
shared vision and cultural fit of the combined companies, the market
opportunities they address and the strength of our people, products and
partners."

About Analytic Applications

Analytic applications help businesses, not-for-profit institutions and
government agencies improve operating efficiency and maximize performance by
providing timely, accurate information and improved process control for better
decision making. Analytic applications can be delivered in three ways: custom,
on-demand and packaged solutions. Custom applications are solutions highly
optimized and tailored to address company-specific requirements. On-demand
applications are solutions rapidly defined and deployed to meet ad hoc business
analysis needs. Packaged applications are purpose-built solutions, defined and
optimized for specific business processes. Leading analytic applications today
include profitability analysis, budgeting and planning, channel analysis,
performance measurement and financial reporting and consolidation. Emerging
market opportunities for analytic applications exist across a broad array of
business functions including sales, marketing, manufacturing, risk management
and human resources. OLAP technology provides a critical component for many of
these applications because of its multidimensional calculation and navigation
capabilities.

About Arbor Software

Arbor Software Corporation (Nasdaq: ARSW) develops and markets enterprise OLAP
software for management reporting, analysis and planning applications. With $82
million in revenues for the twelve months ended March 31, 1998, the company's
products are used by more than 1,600 corporations worldwide, spanning a broad
range of industries, business applications and enterprise data warehousing
architectures. Arbor's customers include BankBoston, Los Angeles Times, PepsiCo,
Prudential and Sears. Arbor's products are sold direct, as well as through
system integrators and resellers worldwide, including Comshare, Fujitsu, i2
Technologies, IBM, Lawson Software, Mitsubishi, PeopleSoft and Walker. Arbor's
offices are located in Atlanta, Boston, Chicago, Dallas, Houston, Los Angeles,
New York, Sunnyvale, Washington D.C., Frankfurt, Hamburg, London, Munich, Paris
and Sydney.

Information on Arbor products and services can be found at
http://www.arborsoft.com. Arbor can also be reached via e-mail at
info@arborsoft.com or by calling 1-800-858-1666.

About Hyperion Software

Hyperion Software Corporation (Nasdaq: HYSW) provides software solutions for
better business understanding and improved financial performance. Hyperion's

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Internet-enabled applications support and enhance enterprise-wide processes
including planning, budgeting, forecasting, consolidation and business analysis.
With $271 million in revenues for the twelve months ended March 31, 1998, the
company's solutions are in use by more than 3,300 organizations worldwide.
Hyperion's customer base includes more than 50 percent of the Fortune 500 and 40
percent of the Financial Times European Top 100. The company is ranked first
worldwide in budgeting software revenue by International Data Corporation and
first in financial OLAP applications by The OLAP Report. The company is
headquartered in Stamford, Connecticut, and has more than 1,300 employees
worldwide. Additional information is available online at
http://www.hyperion.com, or by calling 1-800-286-8000.

This press release contains forward-looking statements relating to the proposed
strategic combination of Arbor and Hyperion, the integration of their businesses
and technologies and the expected benefits therefrom, and such statements
involve a number of risks and uncertainties. Among the important factors that
could cause actual results to differ materially from those indicated by such
forward-looking statements are the satisfaction of various closing conditions,
including receipt of regulatory and stockholder approvals, challenges associated
with the integration of Arbor and Hyperion and their respective businesses and
technologies, competitive pressures, market acceptance of products, changes in
customer requirements, general economic conditions and the risk factors detailed
from time to time in Arbor's and Hyperion's periodic reports and registration
statements filed with the Securities and Exchange Commission, including without
limitation Arbor's quarterly report on Form 10-Q for the quarter ended December
31, 1997 and Hyperion's Annual Report on Form 10-K for the year ended June 30,
1997 and its quarterly report on Form 10-Q for the three months ended March 31,
1998.

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PR Hotline: For media and industry analyst calls on the day of the announcement,
please dial (203) 703-4101 or (203) 703-4102.

Note to Editors: Arbor and Essbase are registered trademarks of Arbor Software
Corporation. Hyperion, Hyperion Software and the Hyperion Software Logo are
registered trademarks of Hyperion Software Operations Inc., a wholly-owned
subsidiary of Hyperion Software Corporation. Any other product or company names
may be trademarks or registered trademarks of their respective owners.

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Contacts:

Joanna McMillan
Arbor Software
(408) 541-4035
jmcmillan@arborsoft.com

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lan Mangelsdorf
Hyperion Software
Phone: (203) 703-3137
alan_mangelsdorf@hyperion.com