Seagate Technology — Director's Dealing 2012

May 16, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Seagate Technology plc (STX)
CIK: 0001137789
Period of Report: 2012-05-14

Reporting Person: MASSARONI KENNETH M (EVP,General Counsel, CAO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-05-14	Ordinary Shares	M	50000	$24.125	Acquired	70429	Direct
2012-05-14	Ordinary Shares	S	50000	$32.00	Disposed	20429	Direct
2012-05-15	Ordinary Shares	M	5000	$3.345	Disposed	25429	Direct
2012-05-15	Ordinary Shares	S	5000	$31.46	Disposed	20429	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-05-14	NQ Stock Options	$24.125	M	50000	Disposed	2013-05-15	Ordinary Shares (50000)	Direct
2012-05-15	NQ Stock Options	$3.345	M	5000	Disposed	2016-03-06	Ordinary Shares (5000)	Direct

Footnotes

F1: Shares were sold under a 10b5-1 Trading Plan adopted by the REporting Person on November 17, 2011.

F2: Options granted to the Reporting Person under the Seagate Technology's 2004 Stock Compensation Plan are subject to a four year vesting schedule. One quarter of the option shares vested on May 08, 2007. Following continuous employment, the remaining shares vest proportionally monthly over the 36 months following May 08, 2007.

F3: Options granted to the Reporting Person under the Seagate Technology's 2004 Stock Compensation Plan are subject to a four and half year vesting schedule. One quarter of the option shares vested on September 11, 2010 . Following continuous employment, the remaining shares vest proportionally monthly over the 36 months following September 11, 2010.