I'm what most of you would consider a wall street person: I'm a high frequency trader, have been for the past decade, and make my income solely from trading.
I own ~4 bitcoins that I mined myself a couple years back just because I thought/think the bitcoin project is cool.
I'd like to buy many, many more bitcoins (to buy and hold, not to HFT). Putting a few hundred thousand dollars into an investment like bitcoin would be something I'd be happy to do - the risk adjusted returns are within my risk profile. I haven't. The reason is I don't trust any of the exchanges. Even the 'reputable' ones are still small/unproven startups. Coming from the wall street world, there's a lot to be said for the security that larger battle-tested financial institutions offer. When you're talking about putting hundreds of thousands to millions of dollars at risk, counterparty risk is a very real concern. At this point in time, no exchange has given me enough faith to trust them with my money, even if it was only for a single hour where I wired it to them and then bought the BTC and transferred the BTC out immediately. While I never would have used gox, just as an example: What if the company happens to blow up in that hour, and I never get my BTC and my USD are stuck in some sketchy small company that is in a foreign bankruptcy proceeding for the next three years?
Wall street types are happy to accept financial risk, but aren't very fond of counterparty risk, especially if we can't hedge it off onto someone else. At the moment that's not particularly possible. If you got even a single reputable financial institution (bank, equity/commodity exchange, something of that nature) to operate a BTC exchange, we'd come flocking.
All of the "fear of the unknown" type comments aren't particularly accurate about why wall street isn't investing bigtime in BTC yet. Wall Street will invest in pretty much any asset as long as the asset provides appropriate levels of risk adjusted returns -- certain assets are clearly far more risky, however, if the returns are sufficient for that level of risk, and that type of investor is able to stomach that risk, they'll happily invest. Imho, BTC has a track record long enough at this point with returns high enough to make it an interesting risky investment for many many institutional investors -- aka, the returns aren't the problem. For example, ask anyone who trades long-dated far-out-of-the-money options how they feel about risky investments. In my opinion, the reliable, safe infrastructure simply isn't there yet to get institutional investors to feel comfortable trading BTC -- it's too much the wild west, with small fly-by-night companies (gox, btc-e, etc) having large market share in the exchange markets.
Just my $0.02.
Don't understand your point? If you want buy and hold you don't must leave your coins/money at any untrustful exchange. Buy few coins and send the coins to you wallet and keep the coins safe. Or buy at local Bitcoin seller, or buy in many steps small amounts at any exchanger (even to avoid to affect the price with your hundreds or millions of $$
)...or or or... Many many possible and safe ways to do...Easy as that...
If you are that big stockmarket trader as you say (doubts are allowed) you might be able to handle risk of small amounts. You gonna lose same or more at stock market trades everyday.