At tor.com, this post by James Davis Nicholl: Risky Business: Five Books About Interplanetary Trade
The book I instantly thought of is on this list: Trading in Danger by Elizabeth Moon. That’s part of the Ky Vatta series, which is quite good space opera.
So is Merchanter’s Luck by CJC. That’s a story I like quite a bit, even though the whole plot turns on emotional angst. CJ Cherryh can make that work for me, unlike practically any other author on the planet.
I’ve got two obvious contenders for a list like this:
1) Quarter Share and associated titles by Nathan Lowell. These are self-published and there are a few rough edges which Lowell sanded off in other titles he wrote later. On the other hand, I like this series quite a bit and have read it several times. And it’s most definitely ALL ABOUT interplanetary trade.
2) Balance of Trade and the other Liaden novels by Sharon Lee and Steve Miller. Some focus more on trade than others, but that’s an important element in this series.
I’ll bet there are plenty of others. Mostly they probably feature peaceful traders who Get Into Dire Trouble, but there’s something to be said for stories like Lowell’s, where as a rule Dire Trouble does not happen and trade is actually front and center for the entire story.