Inside, you’ll find the usual hodgepodge of homegrown businesses: a marine-parts supplier, a local newspaper, a U-Haul rental facility, and so on.But up on the third floor, in suite 3G, one of China’s financial heavyweights has quietly teamed up with a star Wall Street bond trader to make big bets inthe U.S. Treasury market.

The outfit goes by the somewhat unwieldy name of CCSZF Management. The firm is backed by a Citic Group unit, which supplied the seed money, while Industrial & Commercial Bank of China Ltd. was brought in to provide financing in return for a cut of the profits. The key man behind it all is Stephen Siu, who spent two decades helping to pioneer arbitrage strategies for Treasuries on the proprietary trading desk at Greenwich Capital Markets, which later became part of Royal Bank of Scotland Group Plc. Former colleagues describe Siu as one of the savviest traders around, with a keen eye for exploiting minuscule price gaps between the bond and futures markets.

“He is the real deal,” said David Ader, who worked with Siu at Greenwich in the mid-2000s and has been the top-ranked U.S. rates strategist inInstitutional Investor’s annual survey for 11 straight years. […]