The Idea Factory - The Protected
The book starts off with a group of women in a transport van. They're all chained up and scared. When they're pulled out, they're brought to a stage where they are stripped and auctioned off. When the main meets with the person who bought them, they say "I have good news and I have bad news. You are now the property of the United States."
As the story unfolds, the main finds out that the world has completely changed since they were first kidnapped. A virus ran through the human population devastating it. All women that weren't being protected by those particular traffickers are dead, leaving the countries of the world scrambling to buy those remaining, with the hopes of repopulating. It's kind of a darker version of the handmaid's tale.