Here is a list of the largest insurance companies in the United Kingdom ranked by total assets. Headquartered in London, Prudential plc is the largest British insurer with assets of £509 billion and more than 25 million life customers. The company is listed on the Hong Kong, London, Singapore and New York Stock Exchanges, with a market capitalization of US$51 billion as of August 5, 2019. Legal & General plc is the second-largest insurance company in the UK in terms of total assets as well as the biggest provider of individual life insurance products in the country. With over 7,500 employees, it offers life and health insurance products, general insurance, asset management and pension services.

Rank Company Total Assets, £b (12/2018)
1 Prudential plc 508.645
2 Legal & General Group 492.517
3 Aviva plc 430.478
4 Phoenix Group Holdings 229.98
5 AEGON UK 79.184
6 RSA Insurance Group 20.293
7 NFU Mutual 18.241
8 Liverpool Victoria (LV=) 17.925
9 AIG Europe Limited 16.916
10 Standard Life Aberdeen 12.517
11 Direct Line Insurance Group 9.535
12 AXA UK 8.100
13 Chesnara PLC 7.817
14 Allianz Insurance plc 5.893

Aegon UK is the brand name for Scottish Equitable.
NFU Mutual is a trading name for National Farmers Union Mutual Insurance Society, the UK's leading rural insurer.
AIG Europe Ltd (AEL) is one of the largest property casualty insurance companies in the UK by gross written premium.
Allianz Insurance is one of the top 10 general insurance groups in the UK.

Top UK Insurance Companies by Market Cap

Following are the largest insurance companies in the UK based on market capitalization.

Rank Company Market capitalization, £b (August 5, 2019)
1 Prudential plc £41.61 B
2 Aviva plc £15.70 B
3 Legal & General £15.03 B
4 Standard Life Aberdeen £6.86 B
5 RSA Insurance Group £5.50 B
6 St. James's Place £4.99 B
7 Phoenix Group £4.76 B
8 Direct Line Insurance Group £4.28 B