Since Jan. 1, the most popular stocks among Republicans in Congress have made those members collectively at least $5.6 million richer -- and perhaps up to $16 million. The most popular stocks among Democrats have added between $1.8 and $5 million to their aggregated net worth.

When the research organization MapLight released data on Congress members' stock ownership last week, we asked them to break down stock popularity by party to see if we could figure out which party made better bets on Wall Street. They obliged, giving us a list of stocks held by at least 10 members of each party as reported on the personal financial disclosures each member of Congress files with the government. (Those reports only offer ranges of values, which is why we can't be more specific in the calculation above.) The most popular stocks held by members of both parties in 2013 are below.

A few things are noticeable right away on this chart. Some stocks are far more popular with Republicans than Democrats -- note ExxonMobil, for example. In general, there were large differences in the popularity of stocks by type between the two parties. Breaking down the stocks into rough groups, those differences become stark.

Republicans were more likely to own stock in energy and health-care companies than Democrats, and their picks did better. Republicans also were the only ones to make railroad stocks popular, an industry that's seen a boon of late thanks to increased oil production. Democrats, meanwhile, picked better-performing tech and consumer stocks.

On the whole, though, the increases in the two parties' portfolios have been about the same since the beginning of the year. Republicans' popular stocks have gone up almost 8 percent in value; Democrats' just over 7. But since June, the Democrats have done better. Most of the year's increase has been in the last five months.

The long story made short: If you want to invest in energy and finance companies, check out where congressional Republicans are putting their money. If you want to make money in tech, follow the Democrats' lead. We can't guarantee that you'll see your portfolio grow from $209 to $225 million -- the upper limits of what the Republicans' may have done -- but it seems like pretty decent advice regardless.