* A private investment group that includes...

* A private investment group that includes investor Warren Buffett could face competition in a $2-billion deal to buy MidAmerican Energy Holdings Co. as speculation builds that another suitor may emerge for the Iowa utility. Since the deal was announced Monday, analysts and investment bankers have said the firm is worth more than the $35.05 a share being paid by the group, which also includes MidAmerican Chairman David Sokol. They are also questioning the negotiation process used by MidAmerican, which never formally put the firm up for sale. The deal calls for the group to take MidAmerican private in a cash transaction.