The FCA is to investigate the investment and corporate banking markets over fears clients may not be receiving value for money.
The regulator is also set to investigate competition in the asset management sector, with a probe likely to take place later this year.
A previous wholesale sector review found limited clarity over price and quality of services may make it difficult for customers to ascertain value for money.
The regulator is also concerned bundling and cross-selling of services may limit opportunities for new entrants to challenge established players.
FCA director of strategy and competition Christopher Woolard says: “What was clear from the discussions we had with stakeholders and firms was that there are unanswered questions about potential conflicts of interest and value for money in this market.
“This will form part of our wider work in the wholesale markets, alongside the Fair and Effective Markets Review.”
The inquiry comes ahead of new powers which will be granted to the FCA from April this year, allowing it to take action against breaches of the Competition Act and to refer markets to the Competition and Markets Authority for further investigation.
Terms of reference for the investment banking investigation will be published in Spring.