Where to 'park' excess cash while waiting to invest

[Kush Khandelwal]

I'm thinking of doing a cash out refi on my home to use for investing in property. I think I can cash out upto 600K or so with the purpose of using that amount to start down paying for my investments. However I'm unlikely to use all of that amount right away. Any suggestions on how / where to 'park' any excess money while I wait for those investments to gradually materialize?