I was told on the adsense forums that it was very difficult to get approved for publishing on a finance-related website unless you were like a well-known and highly regarded figure in the finance industry. I had applied for adsense a few times for a site that I run which lets people do paper trading of stocks and bitcoin (
www.demoinvestor.com) and was rejected for insufficient content. I started adding some posts and applied again with the same rejection, but maybe I just haven't added enough content yet.