Zurich Insurance Group has confirmed its interest in acquiring British company RSA Insurance Group.

Zurich made two statements last week, one saying it is “evaluating a potential offer”, and another the next day saying “any offer, if made, will be solely in cash”.

Analysts have interpreted this as an indication preparation for a bid is well advanced, although RSA said last week it has “not held talks with or received a proposal from Zurich”.

Zurich may be waiting until RSA delivers its interim results on Thursday, observers say.

This leaves RSA open to interest from other potential suitors, including Allianz and Axa.

Analysts expect a takeover valuation for RSA of £5.5 billion to £5.7 billion ($11.8 billion to $12.2 billion) – similar in scale to UK insurer Aviva’s £5.6 billion ($11.9 billion) acquisition of Friends Life in March. A bidding war would see it eclipse what was the biggest acquisition of a UK insurer.

RSA, described by one analyst as “a perennial takeover story” in recent years, appointed former Royal Bank of Scotland CEO Stephen Hester in February last year to turn it around.

Three profit warnings in six weeks, an accounting scandal in Ireland and the resignation of CEO Simon Lee without a successor in place preceded Mr Hester’s appointment.

He brought in a new management team and implemented an asset sale plan.

RSA traces its roots to the Sun Fire Office in 1710 and wrote its first policy in Australia in 1833. Formed from the merger of the London-based Royal and Sun Alliance insurance businesses in 1992, the company floated its Australian general, life and investment company assets in 2003 under the new name of Promina. The float raised $1.88 billion.

Promina was bought by Suncorp in 2007 for $7.9 billion.