On the 8th April 2015, Shell 8 April 2015, announced the takeover for BG plc. The cost to Royal Dutch Shell is £47 billion

[http://www.shell.com/global/aboutshell/investor/news-and-library/2015/recommended-cash-and-share-offer-for-bg-group-plc.html]

To put things into context, Royal Dutch Shell plc one has to understand the size of Shell.
Royal Dutch Shell’s share capital is made up of two types of shares: Shell A and Shell B

[http://www.shareshop.hsbc.co.uk/shareshop/security.cgi?username=&ac=&csi=133655&record_search=1&search_phrase=shell]

Shell A is worth £78 Billion

[http://www.shareshop.hsbc.co.uk/shareshop/security.cgi?username=&ac=&csi=133755&record_search=1&search_phrase=shell]

Shell B is worth £50 Billion

BG Group is the exploration and production arm of the 1986 new floated British Gas

[http://www.shareshop.hsbc.co.uk/shareshop/security.cgi?username=&ac=&csi=10017&record_search=1&search_phrase=BG]

BG plc is worth £40 Billion