Some treasurers are moving more cash into bank accounts in an attempt to derisk their portfolios, stay highly liquid, and get the peace of a federal guarantee. But money-market funds are still relatively safe places to park cash short term, largely because of the Securities and Exchange Commission’s 2a-7 rules that took effect last year. Money-market funds now have to hold 10% of their portfolios in instruments maturing overnight and 30% in investments maturing within seven days.

But many treasurers (and other investors) still can’t shake the memory of September 2008, when, spurred by the Lehman Brothers bankruptcy, 31 rated funds suspended redemptions and delayed distributions. Shareholders in two funds had principal losses; other funds had to be bailed out by their parent companies.

While there were many causes of that particular market crisis, it revealed a common practice: corporate treasurers relying on fund ratings from agencies to direct their investments, instead of digging deeper to discern which assets the funds were holding. “When the Reserve Fund ‘broke the buck’ and started a run, it wasn’t because of credit issues,” says Jeff Jellison, North American CEO of ICD, makers of an institutional money-market-fund portal. “It was [because of] the unknown.”

Jellison believes lingering anxiety about money-market funds can be dispelled with more transparency on fund holdings, greater diversification by treasurers, and better corporate investment policies. To aid treasurers, consultancy Treasury Strategies has released some guidelines on money-market-fund investments that could help companies “define their risk management investment policies.” The guidelines have been built into Transparency Plus, ICD’s compliance management and reporting application.

Here are six of the parameters:

1. Investment in any single money-market (MM) fund. As a percentage of total investment in MM funds, Treasury Strategies recommends a maximum range for investment in a single fund of 10% to 35%. Just under half of company policies have any set limit, says the consultancy.

2. Investment in a fund’s total assets under management. The recommendation is to set a 5% maximum investment of a fund’s total AUM.

3. Investment in any single fund family as a percentage of total investment in MM funds. Treasury Strategies suggests a maximum investment of 50% to 100%. Corporations can go this high if they have a significant relationship with the fund or bank, and provided the company is diversified in multiple asset classes. For most companies this will not apply, and the portfolio will fall well under this range.

4. Investment in any single issuer (across funds) as a percentage of total investment in MM funds. Most companies should set this ceiling at 3% to 5% for nonsovereign issues, says Treasury Strategies. For sovereign issues, the limit could be significantly above 5%. Regardless, “you don’t want to be overconcentrated in any one credit,” says Jellison. Only about one-fourth of investment policies include these kinds of limits.

5. Investment in rated MM funds. Although the new 2a-7 regulations on money-market-fund holdings encompass both rated and nonrated funds, Treasury Strategies still thinks no less than 60% of a client’s assets should be in rated funds. About 20% of MM funds aren’t rated, Jellison says, because either (a) the fund company feels a rating is redundant with the 2a-7 requirements or (b) the fund would rather not incur the cost of a rating, which it would have to pass along to investors through a management fee or expense ratio.

6. Investment in any single country as a percentage of total investment in MM funds. This standard is based on the domicile of the issuers in a fund’s portfolio. Treasury Strategies advises that companies invest no more than of 50% of their money in issuers headquartered outside the company’s home country.

“If companies had these parameters three years ago, the Reserve Fund would never have quadrupled in size in a four-year period,” says Jellison. “There would have been issues with concentration [of holdings]. There would have never been a blowup and a run.”