EVERY Real Estate Company's: Listings, Foreclosures, Short sales, Estate sales, Bankruptcy, Pre-foreclosures... etc...
Fourplexes are much more management intensive... and have higher vacancy rates than Duplexes... and are usually not in the "best" neighborhoods. Most of them have not been keep up too well. Most investors are not experienced with the realities of rental properties, as can be seen in the relatively short time a Fourplex is owned! Generally I believe Foreplexes are over priced by the inexperienced ("Wanna-Be Investors) paying too much. Be careful! Make accurate cash-flow projections before buying!