Who is the best merchant in Skyrim? (Including those from the DLC)

I recently went to Riverwood, knowing the Riverwood Trader was the merchant with the most gold, allowing for me to sell off all of these things I no longer needed. Problem is, when I went there he only had ~2000 gold. Normally he would have around 11000, so I waited a few days, but there was no change. I suppose they altered the amount of gold he has to offer in the most recent patch and I haven't noticed it up until this point. Anyways, do you guys happen to know any other merchants with more gold to offer than average? Perhaps someone who used to be second best to the Riverwood Trader? Any suggestions will be appreciated!