ISTANBUL The US on Friday ended the “de minimis” tariff exemption for packages valued at $800 or less, closing a major loophole and disrupting international shipping. The change means most commercial parcels will now be subject to tariffs, prompting widespread suspensions worldwide. Letters, documents and gifts valued at under $100 between private individuals will remain exempt. According to the White House, starting Aug. 29, tariffs on small packages will be calculated either by a flat rate of