Report: Citigroup to Bid for Cazenove  LONDON (Reuters) - U.S. investment bank Citigroup is set to  bid for UK stockbroker Cazenove &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=CAZ.UL target=/stocks/quickinfo/fullquote"&gt;CAZ.UL&lt;/A&gt;, challenging rivals JP  Morgan &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=JPM.L target=/stocks/quickinfo/fullquote"&gt;JPM.L&lt;/A&gt; and Lehman Brothers &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=LEH.N target=/stocks/quickinfo/fullquote"&gt;LEH.N&lt;/A&gt; for the City's most  venerable institution, the Observer reported.