ELECTRO SCIENTIFIC INDUSTRIES, INC. SHAREHOLDER ALERT

Rigrodsky & Long, P.A. Announces Investigation Of Buyout

Rigrodsky & Long, P.A.:

• Do you own shares of Electro Scientific Industries, Inc. (NASDAQ GS: ESIO)?
• Did you purchase any of your shares prior to October 30, 2018?
• Do you think the proposed buyout is fair?
• Do you want to discuss your rights?

Rigrodsky & Long, P.A. announces that it is investigating potential legal claims against the board of directors of Electro Scientific Industries, Inc. (“ESI” or the “Company”) (NASDAQ GS: ESIO) regarding possible breaches of fiduciary duties and other violations of law related to the Company’s entry into an agreement to be acquired by MKS Instruments, Inc. (“MKS”) (NASDAQ GS: MKSI) in a transaction valued at approximately $1 billion. Under the terms of the agreement, shareholders of ESI will receive $30.00 in cash for each share of ESI common stock.

If you own common stock of ESI and purchased any shares before October 30, 2018, if you would like to learn more about this investigation, or if you have any questions concerning this announcement or your rights or interests, please contact Seth D. Rigrodsky or Gina M. Serra toll-free at [phone], by e-mail at [e-mail], or at https://www.rigrodskylong.com/offices-contact.

Rigrodsky & Long, P.A., with offices in Delaware, New York, and California, has recovered hundreds of millions of dollars on behalf of investors and achieved substantial corporate governance reforms in numerous cases nationwide, including federal securities fraud actions, shareholder class actions, and shareholder derivative actions.

Attorney advertising. Prior results do not guarantee a similar outcome.

View source version on businesswire.com: https://www.businesswire.com/news/home/20181030006188/en/