Some 2.48 million complaints about financial products generally were made against firms between July and December of last year.
But that figure represents a 15% drop on the previous six months, according to figures released by the Financial Conduct Authority (FCA).
The latest figures also show that banking-related complaints fell to a seven-year low, although gripes about current accounts have shot up by 8%.
The data adds to evidence that the PPI scandal appears to have peaked, although nearly 3.2 million complaints were received about the insurance over the whole of last year.
Just under 1.4 million PPI complaints were recorded in the second half of 2013, which is a 22% drop on the first half of 2013.
PPI now accounts for a lower proportion of complaints made to financial firms, at just over half (56%), compared with nearly two-thirds (62%) in the first half of 2013.
Eric Leenders, executive director of retail banking at the British Bankers' Association (BBA), said of the latest figures:
"Banks are determined that there will be no repeat of any of the bad practices which caused mis-selling in the past."
The FCA also named Barclays as the most complained about firm, followed by Lloyds Bank, MBNA, Bank of Scotland and NatWest.