The collapse of the gold pool forced an official policy of maintaining a two-tiered market system of stipulating an official exchange standard of US$35, while also allowing open market transactions for the metal.[note 1] Although the gold pool members refused to trade gold with private persons, and the United States pledged to suspend gold sales to governments that traded in the private markets,[16] this created an open opportunity for some market participants to exploit the gold window by converting currency reserves into gold and selling the metal in the gold markets at higher rates.