Apportionment of Tax Base

Vesuvius plc and Cookson Group plc

Vesuvius plc shares were admitted to trading on the London Stock Exchange at 8.00 a.m. on Monday 17 December 2012, following the completion of the Cookson Group plc scheme of arrangement, which effected the demerger of the Performance Materials division of Cookson Group plc to Alent plc. In accordance with the terms of the scheme, Cookson Group plc shares were delisted from the London Stock Exchange and cancelled on 17 December 2012. For each share in Cookson Group plc, shareholders were allotted one Vesuvius plc share. For each Vesuvius plc share held as at 18:00 on 18 December 2012, being the demerger effective time, shareholders were allotted one Alent plc share.

Apportionment of Tax Base Cost of Cookson Group plc Shares Between Alent plc Shares and Vesuvius plc Shares

Based on the share prices of Alent plc and Vesuvius plc on 19 December 2012, a shareholder's base cost in Cookson Group plc shares for UK capital gains tax purposes will be allocated 48.87% to Alent plc and 51.13% to Vesuvius plc.

Similarly, based on the share prices of Alent plc and Vesuvius plc on 19 December 2012, a shareholder's tax basis in Cookson Group plc shares for US federal income tax purposes will be allocated 48.87% to Alent plc and 51.13% to Vesuvius plc. US shareholders are referred to IRS Form 8937 for more information.