The UK’s takeover panel said that resource group Xstrata (LSE: XTA) must make an official offer by October 20 to take over competitor Anglo American (LSE: AAL) or issue a statement specifying it is not going to make an offer, Anglo American said in a release Friday. If Xstrata announces it does not plan to make a formal bid, the takeover panel will prohibit the company or any other organization linked to it from making an offer for Anglo American for six months from the date of the announcement.