I'm going to preface this by saying it's not the end of the world, but it's really annoying.
>Half the reason I set up home in riften was because of the huge amount of merchants + thieves guild fence
>some mod (most likely requiem) prevents you from investing in minor merchant shops with the speech perk
>These table stall merchants don't reset their gold either, ever
>Tonilia (the fence) has like 200 gold and only goes up as you complete the thieves guild questline (radiant reputation quests don't count)
>The thieves guild merchants that you get from the radiant quests also can't be invested in and they only have like 1000 gold
That means there's basically only four real merchants in riften, while whiterun has six.