When obtainable, bullion is preferred for shipment abroad, but as a rule the supply of large bars is more or less limited. When shipments are heavy, gold coins of the denomination of 10's and 20's are used, preference being given to the latter, as they are likely to average better and the loss from abrasion is not so great. In shipping gold coin abroad, credit is given for the actual weight of the gold and not the nominal value. Each of the various denominations of gold coins is put up by the United States Mint in bags of $5,000 each, the standard weight of which is 268.75 ounces Troy, or about 18.5 pounds avoirdupois; but many bags weighing less are current, and any such bag is likely to contain many coins below the limit of tolerance, that is, coins which have lost their legal-tender quality because of deficient weight. As these short-weight coins are not current, they are stamped "light" by the government, and must then be sold as bullion, the loss varying from 1/2 to 1 per cent.