I am seriously considering opening my arbitrage program to outside money after my next upgrade, but there would be a handful of unique benefits to any investors:
1: investment may take the form of a bond. So, if I lost the money, I would be held legally liable and my personal property could be taken to repay investors. This is a big deal - there is no way to run away from investors in this scenario. Also, investors would have access to my personal and contact info.
2: All funds, both principal and interest, would be returned simultaneously to all investors on regular cycles. This works well with the bond form of investment, and proves that the investment can't be a ponzi scheme because it's not possible to use Peter's money to pay Paul when both Peter and Paul get their money back at the same time. All investors would be required to submit their deposit address when they first join, so I could ensure that everyone gets their money back exactly as scheduled.
3: Because it's a bond, investors would have a promised return amount, and they would get the amount whether my program is profitable or not. If I don't make profit, then I would pay the interest out of pocket.
4: I would show some of the security precautions over the program - things like professional off-site hosting, encryption, etc.
5: I attend major Bitcoin events and am more than willing to meet potential investors or partners

I wanted to wait for the crazy money and fraudulent HYIP to go away, because there is no way for an honest program to compete with the ridiculous claims of 100% profits in a month that some of those things promised. Unfortunately, almost all of those programs failed and the thieves are nowhere to be found. I expected scammers to be caught and brought to justice and this would discourage future scams, but this has yet to happen.