Bonus curb workarounds being developed by banks from HSBC Holdings Plc to Lloyds Banking Group Plc will be scrutinized by European Union regulators for possible breaches of the bloc's rules. Banker pay limits approved by the EU last year that ban bonuses worth more than twice fixed pay are being put to the test by new remuneration structures at lenders. The approach pioneered by some U.K. banks entails paying staff partly through "allowances" that can vary year to year, and that aren't counted as variable pay.