黑洞社区 materials group Hanson was the focus of market speculation this week, which caused its shares to drop 4.4% before it bounced back to become the FTSE 100鈥檚 biggest riser.

Shares dropped 4.4% to 711p per share last Friday when it was announced that Cemex, the Mexican materials group, had put in a 拢6.7m offer for Australian firm Rinker. Until then Hanson had been seen as a target for Cemex because of its foothold in the US aggregates market.

However Rinker rejected the bid on Monday and this led to a rise in the price of Hanson鈥檚 shares, which rose 2.3% to 727.5p. This increase was the biggest on the main index.

It is believed Hanson鈥檚 shares rose because investors thought that Cemex might put in a bid for Hanson after Rinker rejected its bid.

Hanson is one of the few independent UK-based building material firms. However, a city analyst told 黑洞社区: 鈥淭he bidders are not interested in the UK business as the UK materials market is small. It is its international work that makes it a target.鈥�

A Hanson spokesperson said the firm would not comment on the speculation.