In those cases where merchants are not in a typical category, full details are provided on the specific item types they will buy and sell. The merchandise column provides information on what type of merchandise each merchant will buy and sell. Investing in a merchant improves that merchant's disposition towards you, which can count towards becoming a Thane in the relevant Hold, if you are on the appropriate quest to help members of that hold. These merchants are not checked in the 'Invest' column in the following tables, but instead the bug is noted on the individual merchant page. Some merchants are bugged - they have the dialogue allowing you to pay them 500 gold, but doing so does not result in any permanent change in the merchant's available gold.
The Investor perk allows you to invest 500 gold in certain merchants, after which that merchant will permanently have 500 more gold available.The merchants who have more gold are all identified in the notes of the following tables. The Master Trader perk increases nearly all merchants' gold by 1000.
