Are there any solid securities offered right now? Please join the discussion.
I'd be inclined to say "no" in this case, simply because it's quite a tremulous market right now. As global adoption increases, Bitcoin goes through yet another set of growing pains, and all industries utilizing Bitcoin begin to feel the same pain (to varying degrees).
The increased regulatory concerns around Bitcoin denominated security exchanges has certainly had a negative effect on the market. Tie that in with the vast increase in Bitcoin value and you'll soon find that it may make more sense to just buying and holding coins.
Speaking to mining funds, profit margins (when measured in Bitcoin) will always be decreasing. When thinking long term, this is something should be expected as the difficulty increases. The margins we (in the cumulative sense of KCIM, HIM/HMF, COG, and others) planned for in 2012 (or earlier) were completely overturned by the flood of ASIC developers that have come to market. My guess is that this will continue to happen for quite some time as well. At this point, anyone that promises you hefty mining returns has either never mined before or has no idea how the mining market works.