Paste Enabler, remove attributes from form text fields that restrict copy and paste operations. Tested to be working on many financial websites, though on some it causes duplication (workaround: undo).

bookmarklet

javascript:s=document.createElement('script');s.type='text/javascript';document.body.appendChild(s);s.src='https://goo.gl/OrQlxL';void(0);

pasteEnabler.js

attrs = ["onpaste", "oncopy", "onfocus", "onblur", "onkeyup", "onkeydown", "onkeypress", "ondrag", "ondrop", "onclick", "onmousemove", "onmouseout", "onmouseover", "onchange"];
for (var i = 0; i< attrs.length; ++i) {
    var it = document.evaluate("//input[string-length(@"+attrs[i]+")!=0 and (@type='text' or @type='password')]" , document, null, XPathResult.ANY_TYPE , null );
    var l = []; var t; 
    while (t = it.iterateNext()) {
        l.push(t);
    };
    for (t in l) {
        for (var j = 0; j < attrs.length; ++j ) {
            l[t].removeAttribute(attrs[j]);
        }
        l[t].onpaste = function(e) {
            e.target.value = e.clipboardData.getData('text/plain');
        } 
    } 
}; 
undefined;

@haridsv, I was testing your bookmarklet on https://jsfiddle.net/lesson8/ZxKdp/, but it didn't work. The console spit out these two errors:

• VM2940:1
  Uncaught ReferenceError: Raw is not defined
  (anonymous function) @ VM2940:1
• pasteEnabler.js:10
  Uncaught TypeError: l[t].removeAttribute is not a function
  (anonymous function) @ pasteEnabler.js:10

This is in chromium 51.0.2674.0 on Windows 7. Any suggestions?