While Brexit and trade disputes dominate financial headlines, European Union officials are warning about another risk faced by the bloc and the global economy: the growing importance of new, little-regulated systemic financial actors.

Changes in global financial rules and investment strategies have seen the emergence of new giants in global financial markets in recent years, among them clearing houses like London-based LCH and asset managers such as Blackrock.

EU officials warn the swelling of their books has not coincided with a proportionate tightening of their oversight, however, meaning the potential risks they pose to financial stability are growing. In three confidential EU documents, seen by Reuters, the EU sends hints at new regulations to reduce those risks.

A paper prepared by the Romanian presidency of the EU ahead of an April 5-6 finance ministers meeting invites officials to consider actions to counter challenges to financial stability posed by the asset management industry and clearing houses. Those dangers are further spelled out in a document by the European Systemic Risk Board (ESRB), the body dedicated to protecting the EU's financial stability which is chaired

by European Central Bank President Mario Draghi.

The confidential paper, which will be presented to euro zone finance ministers at the Bucharest meeting, draws up a list of risks to financial stability which include the shadow banking system — another name for asset managers and investment funds.

The threat-list is topped by trade and Brexit dangers, and also mentions challenges to bank funding and debt sustainability risks.

The main reasons for concern over the shadow banking sector are its increasing size and complexity, the high leverage of some funds, lack of risk monitoring and poor transparency.

Blackrock, the biggest of all funds, manages some $6 trillion of assets, making some giant banks look tiny in comparison. Despite that, it faces lighter requirements and less stringent oversight than lenders.

EU finance ministers will raise this issue at the G20 level in a meeting with their counterparts in Washington on April 11-12, where they will urge partners to address, if necessary, "emerging financial vulnerabilities" springing from the sector.

Clearing houses cause similar headaches after their systemic relevance grew with new regulations that require more transactions to be centrally cleared, rather than being conducted bilaterally.

After the last financial crisis a decade ago, banks in Europe were forced to contribute to a new rescue fund and raise fresh buffers that would be used in case they fail, under the oversight of a new body, the Single Resolution Board (SRB), created with the task of disposing of failing lenders.

But this "resolution mechanism" does not cover clearing houses, like the giant LCH, a unit of the London Stock Exchange, which dominates clearing of euro-denominated derivatives worth trillions.

With Brexit looming, the EU has changed its rules in a way that could force LCH to relocate to the bloc after Britain leaves. That is likely to boost the EU's powers of supervision over systemic clearing houses, but not its ability to limit damage in the event they go bust.

Clearing risks extend to large investment banks, like JPMorgan and Goldman Sachs which process huge amounts of securities transactions, the SRB's head Elke Koenig said at a hearing in the European Parliament on Tuesday. "We have not made the progress we should have made on the recovery and resolution" of clearing houses, Koenig told EU lawmakers, stressing the issue should be primarily addressed at global level.