gistfile1.js

// ==UserScript==
// @name         Replace investors.com stylesheet with local copy
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @run-at document-start
// @match        http://www.investors.com/*
// @match        http://www.dev7investors.com/news*
// @grant        none
// ==/UserScript==
/* jshint -W097 */
'use strict';
/*
for (var i = document.styleSheets.length - 1; i >= 0; i--) {
    document.styleSheets[i].disabled = true;
}
*/
window.onload =function(){
    for (var i = document.styleSheets.length - 1; i >= 0; i--) {
        if( document.styleSheets[i].href == 'http://www.investors.com/wp-content/themes/ibd/dist/styles/main.css'){
            console.dir(document.styleSheets[i]);
            document.styleSheets[i].disabled = true;
        }
    }
}



var link = document.createElement('link');
link.rel = 'stylesheet';
link.type = 'text/css';
link.href = 'http://investors.app/wp-content/themes/ibd/dist/styles/main.css';
document.getElementsByTagName("head")[0].appendChild(link);