However, mining is fairly distributed and, because of the ASIC boom, the distribution probably changed from the previous GPU one. I'm not sure how hedge funds would go on about contacting miners due to that distribution, or vice versa. There is no real futures market I'm aware of. If you want to make that case, then I think it's more likely for hedge funds to set up mining operations of their own; purely for accumulation.
In any case, there will be a large portion of the daily mined coins that goes to miners who have no channels to reliably sell Bitcoins other than exchanges – that is my speculation and I believe it's a reasonable and educated guess based on the things I listed here and the previous post.
Right now, supply on exchanges is mildly increasing and if you add up multiple exchanges together, it is not all that low. If there is accumulation, then the accumulators either ran out of powder or they don't wish to accumulate anymore. Of course, this is all too easily visible based on SecondMarket's change in buying behavior alone: https://bitcointalksearch.org/topic/gbtc-bitcoin-investment-trust-observer-337486
I personally believe a substantial number of coins (but still less than 50% of total volume) are sold off-exchange these days, but I admit, there is no way for me to prove my claims either. My main reason for this belief being that there is enough evidence by now that big (or at least: bigger than hobbyist's) money is entering the market, but at the same time, I have a hard time imagining them wiring a few millions over to Japan or Slovenia.
Here's one smaller observation that perhaps matters in this context: If I look at the order book at all, I only consider relative bid/ask ratios, and their change over time, to be half-way reliable. But isolating for a moment the raw ask sum over time, there is, I believe, a pretty clear downwards trend visible over the past years, not easily accounted for by the reward halving alone. Whether that means more holding or more OTC is of course just anybody's guess again. 'Holding' would be bullish across all time frames, while 'OTC' would introduce an element of uncertainty ("maybe they're selling way below mtgox price?!") that could, at least short/medium term, be quite bearish.