It’s not always easy to find out.

Typically, there’s signage posted at the entryway to law enforcement and courts buildings requiring visitors to check their weapons before entering the buildings’ secured areas. There’s very little signage warning investors about weaponry in their exchange-traded fund (ETF) portfolios, however.

In the wake of the Florida school shooting, many current and prospective shareholders worry that they may be inadvertently supporting gun and ammunition manufacturers. Few, however, have taken the time to actually peruse their ETF portfolios for gunmakers’ names. Even if they did, the names don’t jump off the pages of a fund’s prospectus. Oh sure, there’s Sturm Ruger & Co., Inc. (NYSE: RGR), a well-known producer of pistols, revolvers and rifles. That’s pretty obvious. But the famous Smith & Wesson brand is now dressed rather inconspicuously as American Outdoor Brands Corp. (Nasdaq: AOBC). With a name like that, you’d think they made patio furniture, not firearms. Likewise for Vista Outdoor (NYSE: VSTO). At least Vista’s product line includes camping gear along with all the firearms and ammunition.

Did you know chemical maker Olin Corp. (NYSE: OLN) owns the Winchester brand of guns and ammo? Or that National Presto Industries, Inc. (NYSE: NPK), famous for its line of small kitchen appliances, is actually a defense company that makes more money from the sale of ammunition and other lethal materiel than it does from consumer goods?  

There are 99 ETFs marketed in the United States that hold one or more of these gun and ammunition makers. One – the PowerShares PureBeta MSCI USA Small Cap Portfolio (NYSE: AMEX) – holds all five. Others own just a single issue. And, of those, some have rather large positions.

Take the PowerShares DWA Basic Materials Momentum Portfolio (Nasdaq: PYZ) as an example. PYZ tracks a Dorsey Wright index that selects and weights stocks in the basic materials sector on the basis of their price momentum. Currently, PYZ devotes 3.33 percent of its portfolio to OLN.