The fact that CITs don't have ticker symbols makes it difficult to track one's portfolio with online services such as Quicken, notes Lori Lucas, an executive vice president at Callan Associates Inc.

WSJ: Why 'Collective Trusts' Are Worth Considering

Of course, CITs have their drawbacks.

WSJ: Why 'Collective Trusts' Are Worth Considering

In addition, investors will have a harder time getting information on CITs than on mutual funds, which are listed in newspapers and online, says Laurie Nordquist, executive vice president and director of Wells Fargo Institutional Retirement and Trust in Charlotte, N.

WSJ: Why 'Collective Trusts' Are Worth Considering

What's more, workers can invest in collective trusts only in ERISA-qualified plans, according to Ms. Nordquist. (ERISA stands for Employee Retirement Income Security Act.) That means CITs aren't available to retail individual retirement accounts, 403(b)s, government-sponsored 457(f) plans or any executive deferred-compensation non-qualified plan.

WSJ: Why 'Collective Trusts' Are Worth Considering