I wish there was. The only decent investment that I have found is Bitfinex (lending BTC/USD there), and I'm not even sure about that one.
Bitfinex is probably the safest currently.
What exactly? Lending?
Lending in BTC and/or USD. I don't have a lot in there at all but have been doing it for over 2 years, never had a problem.
Lending seems as an interesting option. Have also checked BTClend and other similar sites. The main problem is collateral. None of lending sites has managed to solve this issue.
There is one good lending site where the borrowers can put collateral (e.g. altcoins): BTCPop.
Depending on the rating of the borrowers loans are insured additionally up to 75%. That's why, some loans are no brainers since there is much collateral and/or a high percentage insured.