X0306 4 2013-05-16 0 0001137789 Seagate Technology plc STX 0001197751 MARSHALL LYDIA MICHEAUX SEAGATE TECHNOLOGY PLC 10200 S. DE ANZA BOULEVARD CUPERTINO CA 95014 1 0 0 0 Ordinary Shares 2013-05-16 4 M 0 10000 26.465 A 56181 D Ordinary Shares 2013-05-16 4 S 0 19500 40.7489 D 36681 D NQ Stock Option 26.465 2013-05-16 4 M 0 10000 0 D 2008-10-15 2014-10-25 Ordinary Shares 10000 0 D The price reported in Column 4 is a weighted average price. Shares were sold in multiple transactions at sales prices ranging from $40.68 to $40.8523, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. Options granted to the Reporting Person under the Issuer's 2004 Stock Compensation Plan were subject to a four-year vesting schedule. One quarter of the shares vested on October 15, 2008. The remaining three quarters vested proportionally monthly over the 36 months following October 15, 2008. /S/ Roberta S. Cohen by power-of-attorney 2013-05-17