The instruments available to European legislators are directives and regulations. An EU regulation is binding in its entirety and directly applicable in all member states. A directive, on the other hand, is binding for member states only as to the result to be achieved, which means that it has to be transposed into national law.
European legislation often has its roots in the recommendations of the Basel Committee. For example, Basel III was implemented at the EU level by way of the "CRD IV package" (comprising the Capital Requirements Regulation, or CRR, and the Capital Requirements Directive, or CRD IV).