Organisations which define the rules by which financial institutions carry out their business. An example in the US is the CFTC, in Europe is ESMA and in the UK is the FCA.
A risk factor on a trade could be interest rates, fx rates, equity prices, bond prices, default rates and any other input to measuring the risk of the trade.
A message to a custodian for the Required Value to be matched and funded. This can be achieved using a MT527 SWIFT message.