The G20 ministers asked the Financial Stability Board to conduct an impact study on bail-in proposals that are not yet compatible with EU resolution rules.
Operational challenges raise questions about whether new trading book rules will create more accurate and comparable market risk weightings.
Banks are concerned about the different timescales in the UK, US and Europe, and the risks to cross-border securities trading activities.
As banks digest derivative valuation adjustments for funding, counterparties and fair value, a new set of rules on the horizon will require firms to make prudent valuations of the entire business.
Buy-side and sell-side firms have diverging interests on who pays to rescue a clearing house.
The recent spate of regulatory initiatives and lawsuits aimed at high-frequency trading could light the touch paper for more fundamental US market structure reform.