P.M. Edition for Sept. 13. In the biggest IPO of the year, British chip designer Arm prepares to price its shares at $52 apiece ahead of its trading debut on the Nasdaq on Thursday. Plus, could China weaponize its store of precious metals, as oil- producing countries have with their commodities? Chief economics commentator Greg Ip explai ns why that could mean swapping one commodity dependence for another. And U.S. inflation accelerated in August, due to higher energy prices. Annmarie Fertoli hosts.  Learn more about your ad choices. Visit megaphone.fm/adchoices