The £100,000-a-year account is currently at long list stage and the deadline for entries is 11 July.
Incumbent agency Manning Selvage & Lee has held the account since March last year and has been invited to repitch.
The appointed agency will report to UK head of comms Jon Sellors.
The account excludes the group's More Th>n brand, which was awarded to Cow PR last November (PRWeek, 22 November 2007).
UK external comms manager Simon Kutner said the corporate and business-to-business activity would include a large focus on the broker business. The chosen agency will also be charged with addressing larger insurance issues including fraud.
RSA was formally Royal & SunAlliance but changed its name in April this year. It is the UK's largest commercial insurer with a market share of more than 13 per cent and 20 million customers worldwide.