A recent article in the Wall Street Journal highlighted how some investors are using algorithms to quickly parse housing data and formulate bids on undervalued properties, site unseen. While doing so is a cool technological feat, it can spell trouble for normal people trying to navigate the often complex home-buying process in order to make offers on similar homes. And algorithms aren't the only benefit that more sophisticated investors have. "Investors are winning over the first-time buyers in some bidding processes because investors are all cash," says Lawrence Yun, a chief economist at the National Association of Realtors. For a seller that means a smoother deal: no waiting around on financing, loan approvals or other inconveniences that traditional buyers bring to the table.

Some investors contend that the homes they purchase don't put them in direct competition with first-time buyers. Invitation Homes, an investing and leasing company owned by Blackstone says that they typically funnel another 10 to 12 percent of the purchase price into renovations in order to make a property market-ready—an investment that most first-time home buyers wouldn't be able to afford. Many investors also contend that compared to the number of homes that are bought and sold nationwide, their activity is just a drop in the bucket.

When looking at the big picture, that's true. Nationwide, large institutional investors made up only 4.3 percent of the single-family home purchases in the market during 2014, according to RealtyTrac a real-estate data firm. And overall investment activity is dwindling as home values return to normal and there are fewer deals to be had. Dallas Tanner, the chief investment officer at Invitation Homes says that the group currently buys about $25 to $30 million a week of single-family properties, that's down from their 2012-2013 peak when the group spent upward of $160 million each week.

But like all things in real estate, it's also a matter of location. Lots of investor activity is concentrated in markets where homes are still available at reasonable enough prices that purchasers can turn a profit. According to a February 2015 report from RealtyTrac.