Though the Fed's own data points to a rate hike this summer, Schenk said there's also a good chance nothing will happen in 2015 in part, because of the effects of deflation in the Eurozone and Greece's precarious situation. Slack in the domestic labor market and declining GDP growth in China also weaken the case to raise rates, he noted.

“There's a lot of people that are arguing that the Fed has painted themselves into a corner,” Andrew McGeorge, CFO of the $2.5 billion Service Credit Union in Portsmouth, N.H., said. “Even if the data [doesn't] support it, they might have to make a token rate increase this year, just because they'll lose their credibility if they don't.”

McGeorge added, “If rates go up, it's likely that rates are likely to go up by a larger amount at the short end of the yield curve, especially overnights, two-year, three-year-type things,” Those are the types of investments that will get more play. It will be more enticing to keep money in cash.”

He continued, “A lot of credit unions have completely given up on two-year bullet or two-year callable investments because the yields are so dismal. They're just buying five-year bonds or buying mortgage-backed securities, so it's those types of areas that will likely see the greatest lift.”

Bill Conerly, an economist and business consultant with Conerly Consulting LLC in Lake Oswego, Ore., said duration is a popular topic these days.

“The big thing that people are talking about is should they go longer term or should they stay on the short end of the curve and invest for three months or six months.”

Conerly said he thinks June might be go-time for a Fed rate hike.

“There's not been a lot of interest in long maturities in the last few years, because of this belief that rates are going up and better to keep your powder dry and be ready to invest more at the higher rates,” he noted. “But that has not proved to be a winning strategy.”

Once there is a rising rate environment, credit union treasurers will feel much more confident at extending out the yield curve and going for longer-term notes and bonds, Conerly said.

“I've seen some credit unions that have shortened up in anticipation of [rising rates], and I've seen some credit unions that aren't doing anything about it yet,” Hague said. “At the ones that I've seen, I haven't seen really extreme long duration plays. Those folks should probably move sooner rather than later to restructure, because you know if they wait until rates go up, obviously, they've got to take losses when they sell.”

McGeorge said he's seen more evidence of credit union investment activity in things such as SBA-backed loan pools.

“They offer very good yields,” he said. “They do come with some risks. They're floating-rate instruments with caps, so if you think rates are going to go up a lot, you're not necessarily going to participate in all the upside. I think the liquidity of them is very tenuous. If you get a big portfolio of them and you needed to unload it, you're probably not going to be able to get fair value for them.”

Expected double-digit increases in loan demand in 2015 may have credit unions looking for cash to lend, but in a rising-rate environment, that won't necessarily come from deposits.

“We think there's a lot of money parked in what are traditionally viewed as core deposits that aren't core deposits,” Schenk explained. “It's essentially hot money, and it's sitting there waiting for money market interest rates to go up.”

Money market mutual funds will not lag that increase in cost, so the yields there will go up very, very quickly, and we'll start to see disintermediation, he continued.

“It's going to be a combination on both sides of the balance sheet, probably not declines in savings balances, but very slow growth in savings balances combined with more loan growth, and that's going to say to most credit union investors, 'Gosh, I better have most of my investments in portfolios that can be quickly converted to cash to meet some of these outfalls,'” Schenk said.

The real motivator for change in credit union investments is not so much that rates will be going up a little bit in the near future, he pointed out. It's that loans will continue to grow, and liquidity will become plentiful.

“With tight liquidity, you're going to want to stay short and liquid, and I think, probably obviously, a rising rate environment strengthens that initiative.”

Hague said, “You've got deposits that re-price frequently, and you've got longer-term fixed-rate assets that those deposits are funding and they don't re-price as frequently, and as rates rise, they're even less likely to re-price, because mortgages aren't going to refinance when rates are going up. Obviously, your cost of funds, then, is rising and the earning rate on those assets is not.”

With lower down payment requirements on Fannie Mae and Freddie Mac mortgages, lower FHA mortgage insurance premiums and pent-up demand, 2015 should be solid for housing, Hague said.

“But I would recommend that they sell those loans, because again, we're looking at record low rates. Those loans aren't going to prepay very quickly. So they're going to want to get those low-earning assets off their books,” he said.

On Jan. 15, the NCUA Board issued a second proposed rule on risk-based capital for credit unions that amended a proposal issued about a year ago.

“I think the NCUA's ultimate approach to interest rate risk will be the regulatory driver of how credit unions behave from an investment perspective,” Schenk said.

While the original proposal gave too much weight to interest rate risk and penalized credit unions with longer-term investments and other assets, according to Schenk, the subsequent version offered a breather.

“We've got a longer period of time to adjust to this,” he said. “We're going to see rising interest rates in the short term, and then, four years down the road, have to wrestle with risk-based capital.”

Risk-based capital isn't the only regulatory focus. “The only real change that there's been in the credit union investment regulatory landscape recently has been, and it's not that recent now, has been the expansion of hedging authority,” Hague said. “That's another avenue for credit unions, that they can use derivatives to hedge their interest rate risk. That can be a very effective and cost-effective way to manage interest rate risk if you know what you're doing.”

Still, that strategy is pretty limited, Hague cautioned.“It tends to be the larger and more sophisticated players, or some that are using investment advisers that have some knowledge about those strategies. But even then, I haven't talked to a credit union smaller than a couple billion in assets, at least, that's doing it. Even those are using advisers.”