Citigroup's Krawcheck to Get No. 2 Post  NEW YORK (Reuters) - Citigroup Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=C.N target=/stocks/quickinfo/fullquote"&gt;C.N&lt;/A&gt; on Monday said  one of its fast-rising executives, Sallie Krawcheck, will take  over the No. 2 position at the world's biggest financial  services company, replacing Todd Thomson who will take her job  as head of brokerage Smith Barney.