Ask Matt: Where should you invest $15,000?

• Deciding how much to invest is an important first step
• Online brokerages offer a family of low-cost ETFs that are get for new investors
• Understanding the risk you can stomach is key

USA TODAY markets reporter Matt Krantz answers a different reader question every weekday. To submit a question, e-mail Matt at mkrantz@usatoday.com.

Q: Where should a 50-year old invest $15,000?

A: With thousands of stocks, mutual funds, bond and other investments to choose from, investors often throw up their hands and do nothing.

But, by being very clear in how much you have to invest, you've already made one of the hardest decisions that stymies many beginning investors. Next, though, you need to understand how much risk you can tolerate. Your threshold for risk will be the biggest determinant of how you should invest.

Based on your full question e-mailed to me, you're looking for a simple way to invest money with a brokerage that you don't have to micromanage. For most people looking for a simple way to invest and not worry about it, a blend of a couple exchange-traded funds is usually a blunt but relatively good instrument to use.

One simple strategy would be to put $7,500 of your money in a Standard & Poor's 500 ETF, such as the Vanguard S&P 500 ETF, which trades by the symbol VOO. You could pair that by putting the other $7,500 into the Vanguard Total Bond Market ETF (symbol: BND). Be sure to check with your broker, since it might offer comparable ETFs that come with lower trading commissions.

You can certainly get fancier as you build your savings and add to your portfolio. But for just starting out, this basic asset allocation will get you started.