What do you mean by "pledging" 60% of income on investment? Do you mean you would distribute 60% of mining income (or profit?) as dividends, keeping 40% for yourself? And does "pledge" mean "pinkie swear" or "guarantee with collateral held in escrow" or something in between?
The mining operation may have annual income bigger than 100% if new equipment is purchased to keep against the race of constant difficulty increase of BTC. 60% means guaranteed return after paid all expenses to maintain and replace equipment, administrative costs, electrical bill, taxes, equipment colocation rent, insurance, fire alarm, etc. By pledge I mean promise it is not guaranteed by escrow, just like most if not all companies listed on Cryptostock or Havelock and beyond are not guaranteed by any escrow. Did in the past or does in the present Microsoft guarantee its ROI by escrow? I am sure you know the answer. The investment is risk just like any other investment, all companies that start are new to the market and some of these new companies are scammers, but it doesn't mean that all companies are trying to scam people off their money. New company has no means to secure escrow, just initial investment on equipment is large enough to bear it on our own shoulders and to expand rapidly mining operations from income generated by mining is not possible, because this is slow process due to rapid BTC difficulty change. If we could expand ourselves without external funds we would love to do it that way, to avoid bearing additional responsibilities, but in the real world this is not an option.
I'm reading "60% means guaranteed return after paid blah blah" as you're planning to pay 60% of net profit after all your expenses, and "pledge" means pinkie swear with double retard twist, and guaranteed means fucking monkeys will fly out of my goddamn ass before I ever see any of the money. But please correct me if I'm wrong.