Bad timing to invest in mutual funds?

[nogenius]

Currently, my portfolio consists mainly Vanguard index funds. I recently obtained a significant sum of money that I would like to invest.

However, the market has been experiencing massive increases lately, and there is talk of unsustainability. Although I know that timing the market is impossible, would it be a prudent move to wait a bit to invest the money into the index funds, or just stick it in?

Thanks.

[ilikeaces86_]

Put some in now some in later.

[Pendimethalin]

How long do you plan on keeping this money invested? Is it for retirment or will you want to use it in 2-5 years? If you'll need to use it in 2-5 years put it in something safer like a bond or MM. If it's a long term investment then invest it now. Also if you think you'll just percent of it in 2-5 years you could put that percent in either a MM or bond and the rest in the market.