This is probably a stupid question, but I couldn't find an answer anywhere. I am just starting out and I have a Roth IRA account with an Online broker holding $5500 ready to be invested. I am running into a "market order maximum" problem where I can only invest 95% of my funds in say an ETF. This would leave me with 5% sitting in my account doing nothing. As far as I can tell I would have a similar problem using a limit order where the price of an ETF might not fit evenly into the amount I have to invest.
So my question is: Are there any strategies For investing every penny in this situation without investing in a mutual fund?