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.