David and Simon Reuben are the richest selfmade billionaires in England. Here are their 5 lessons. Secrecy is a Must for Traders. Stak Cash. Chaos means .brSecrets of Self-made Billionaires, how they made their fortunes.brDavid and Simon Reuben are the richest selfmade billionaires in England. They were born to wealthy Iraqi Jewish family in Mumbai India. They made their .