<prompt> Human: Market is crazy high where I live and the opportunity was too good to pass up.Rather than jumping back in to the housing market, we downsized into an apt. We have zero debt, 401ks maxed, and college taken care of for both kids.Our plan is to wait until the housing market settles down and use the 75K as a down payment. Problem lies in whathow to invest so I can access quickly and penalty-free in case the housing bubble decides it is big enough.  <response>: You can cash out almost anything quickly, for some value of quickly, and theres little difference between something penalty-free and something with a very small penalty. So, really, you could do a lot of things.But just to quantify some of these parameters:Lets rule out investing in something highly illiquid, like classic cars, since to sell those quickly, youd probably have to take a fraction of their value. You can sell stocks quickly, but you might be selling at a time when they are not worth as much as they would be in the future, so thats not ideal. You cant predict that, so thats why stocks arent the best for this.You could use CDs, but you would pay an interest rate penalty if you cashed them in early. But its only a reduction of interest you would have got, so a pretty minimalist penalty, all things considered.You could use bond funds, which are similar to stock funds with lower volatility, so less risk of selling at a really bad time, but also historically lower gains than stocks.Or, you could use a savings account, which is accessible quickly and penalty-free, but with minimal interest.You have options. 