套购金银 meaning in English

arbitrage in billion

Article 20 business units must conduct their business within the approved scope , and shall not alter the scope of business without authorization , embezzle gold and silver or use them for any other purpose , or illegally purchase them in the course of their operations
第二十条经营单位必须按照批准的金银业务范围从事经营，不得擅自改变经营范围，不得在经营中克扣、挪用和套购金银。