3 Top Index Funds for Your IRA

Index investing can give you exposure to a lot of stocks all at once, removing the risk of putting all your investment eggs in one basket. Figuring out which index fund to buy, though, can be tricky. There are a lot of index funds and index ETFs to choose from, but three of our top Motley Fool contributors think the iShares Russell 2000 ETF (NYSEMKT: IWM), SPDR S&P Dividend ETF (NYSEMKT: SDY), and the Schwab Total Stock Market Index Fund (NASDAQMUTFUND: SWTSX) make the most sense to buy now. Are these funds right for your portfolio?

Time to think small

Todd Campbell (iShares Russell 2000 ETF): 2017 was a great year for all stocks, but owning small-cap stocks could be the better bet in 2018 and beyond.

The iShares Russell 2000 ETF underperformed the S&P 500 by about 5% in 2017, and as a result, the average stock in the index has a lower price to book ratio and price to sales ratio than the average stock in the S&P 500. Additionally, tailwinds tied to tax reform, wage growth, and a potential increase in infrastructure spending could help small-cap stocks outperform large-cap stocks from here.

A persons hands arranging an upwardly pointing arrow made of cut-up construction paper.
A persons hands arranging an upwardly pointing arrow made of cut-up construction paper.

IMAGE SOURCE: GETTY IMAGES.

Currently, the Russell 2000 and S&P 500 boast similar forward price to earnings ratios, but the Russell 2000's price to book ratio is only 2.15 compared to the S&P 500's 3.1, and its price to sales ratio is just 1.24 versus the S&P 500's 2.28. The Russell 2000's lower ratios suggest investors are undervaluing small company break-up values and revenue relative to bigger peers.

Because small companies in this index get most of their revenue from the U.S. market, their profitability should benefit significantly from dropping the corporate tax rate to 21% from 35%. They'll also benefit most from the change to immediate expensing on certain capital expenditures and from GDP growth due to rising U.S. wages. If an infrastructure spending bill passes in 2018, it could lend even more support to smaller stocks.

Admittedly, small-cap stocks tend to be more volatile, and that makes owning them risky. Rising interest rates can weigh on profitability by increasing borrowing costs, too. Nevertheless, small stocks historically tend to generate greater average annual returns than big stocks, and given these tailwinds, I think it's a good time to begin dollar-cost averaging into the iShares Russell 2000 ETF in retirement accounts.

Did someone say dividend income?

Sean Williams (SPDR S&P; Dividend ETF): With the stock market seemingly hitting new highs every week, many investors are likely eyeing growth stocks. As for me, I believe strong dividend stocks might be the smarter choice over the long run, which is why the SPDR S&P Dividend ETF may deserve a place in your IRA.