Overall, the number of complaints about life and pensions companies jumped by nearly 20% in the first half of the year, standing at 73,055.
FCA figures revealed that Pru received 8,827 complaints in the first six months of 2015, making it the most complained about life insurer in the UK.
Friends Life came second with 7,013 complaints, Royal London came third with 5,688, and Aviva came fourth with 4,342 complaints.
The FCA data also cites a 22.8% rise in complaints about investment management firms, totalling 14,955.
Santander UK was the most moaned about investment firm, with 4,375 complaints. HSBC Bank came second with 2,932, followed by Barclays Bank with 2,759, and Halifax Share Dealing with 1,724.
Addressing the causes
“It is clear that firms need to look at the causes for this rise and where necessary take action to address the causes of the trend,” said the FCA’s director of strategy and competition, Christopher Woolard.
“Ensuring good consumer outcomes should be at the heart of firms’ activities and we want to see complaints fall in the future as firms seek to ensure that consumers get the right products and services.”