Citigroup, Wells Fargo and Bank of America were among the banks that received the most consumer complaints in 2016filed through a federal watchdog agency in 2016. A new analysis by the Consumer Financial Protection Bureau (CFPB) ranked banks by the number of complaints received so far this year, after adjusting for the size of their deposits.

Topping the list was TCF Financial, a MN-based regional bank that received 12.3 complaints for each $1 billion in deposit. Rounding out the ignominious Top 5 were: Citigroup (with 8.6 complaints), Wells Fargo (8), SunTrust Banks (7.7), and Bank of America (7.2). When ranked by the absolute number of complaints, Wells Fargo was #1 with 10,204, followed by BofA with 8,953, and Citigroup with 8,065.

Some bank representatives criticized LendEDU’s methodology, saying it fails to account for different business models that could increase or cut the number of complaints. A TCF spokesman said the study “inflates the ratio of complaints for a bank like TCF which has a higher number of transaction accounts relative to peers with similar deposits.”

Since its launch 5 years ago, the CFPB’s complaint portal has emerged as a go-to venue for consumers frustrated with their financial institutions, and become an important tool for the agency’s inspection and enforcement operations. It has handled more than 1 million complaints, including 27,000 in October.

RELATIONSHIP OF COMPLAINTS AND REGULATORY FINES.    PerformLine, a provider of a regulatory compliance platform, analyzed consumer complaints the CFPB received between December 2011 and July 2016. It found the probability of a company being fined by regulators jumped to 50% when it received more than 2,000 complaints, compared with 6% for companies receiving 100 to 2,000 complaints.