The Fed is running low on ammunition, but not completely out of it. Former vice chairman of Fed’s Board of Governors, Alan Blinder, economics professor at Princeton University, lists four weak weapons the Fed is now left with, and he analyzes how the Fed should use them, and their limitations.  A very insightful piece. (source: WSJ)

You may have noticed that the complexion of the U.S. economy has turned a bit sallow of late. The Federal Reserve definitely has. At its Aug. 10 meeting, the Federal Open Market Committee (FOMC) shifted attention away from its former concern—how to tighten a bit—and toward a new concern: how to loosen a bit. By central bank standards, this turnabout came at warp speed.

Chairman Ben Bernanke has told the world that the Fed is not out of ammunition. It still has easing options, should it need to deploy them. The good news is that he’s right. The bad news is that the Fed has already spent its most powerful ammunition; only the weak stuff is left. Mr. Bernanke has mentioned three options in particular: expanding the Fed’s balance sheet again, changing the now-famous “extended period” language in its statement, and lowering the interest rate paid on bank reserves. Let’s examine each.

• From exit to re-entry. The first easing option is to create even more bank reserves by purchasing even more assets—what everyone now calls “quantitative easing.” The FOMC took a baby step in that direction at its last meeting by announcing that it would no longer let its balance sheet shrink as its holdings of mortgage-backed securities (MBS) mature and are paid off. Instead, it will reinvest the proceeds in Treasury securities.

Two distinct policy shifts are embedded in this announcement. Most obviously, the gradual shrinkage of the Fed’s balance sheet—a key component of its exit strategy—comes to a screeching halt.

Less obviously, the purpose of quantitative easing changes. When the Fed buys private-sector assets like MBS it is trying to shrink interest rate spreads over Treasurys—and thereby to lower private-sector borrowing rates such as home mortgage rates—by bidding up the prices of private assets, and so lowering their yields. Judged by this criterion, the MBS purchase program was pretty successful.

But when the Fed buys long-dated Treasury securities it is trying to flatten the yield curve instead—by bidding up the prices on long bonds. That effort also seems to have succeeded, perhaps surprisingly so given the vast size of the Treasury market. Now put the two together. By reducing its holdings of MBS and increasing its holdings of Treasurys, the Fed de-emphasizes shrinking risk spreads and emphasizes flattening the yield curve. That strikes me as a bad deal for the economy because the real problem has been high risk spreads, not high Treasury bond rates.

If the FOMC is serious about re-entry into quantitative easing, it should buy private assets, not Treasurys. Which assets? The reflexive answer is: more MBS. But with mortgage rates already so low, how much further can they fall? And would slightly lower rates revive the lifeless housing market?

To give quantitative easing more punch, the Fed may have to devise imaginative ways to purchase diversified bundles of assets like corporate bonds, syndicated loans, small business loans and credit-card receivables. Serious technical difficulties beset any efforts to do so without favoring some private interests over others. And the political difficulties may be even more severe. So the Fed will go there only with great reluctance.

• What’s in a word? The FOMC has been telling us repeatedly since March 2009 that the federal-funds rate will remain between zero and 25 basis points “for an extended period.” This phrase is intended to nudge long rates lower by convincing markets that short rates will remain near zero for quite some time.

The Fed’s second option for easing is to adopt new language that implies an even longer-lasting commitment to a near-zero funds rate.

Frankly, I’m dubious there is much mileage here. What would the new language be? Hyperextended? Mr. Bernanke is a clever man; perhaps he can turn a better phrase. But market participants already interpret the “extended period” as lasting deep into 2011 or beyond. How much longer could any new language stretch that belief?

• Interest on reserves. In October 2008, the Fed acquired the power to pay interest on the balances that banks hold on reserve at the Fed. It has been using that power ever since, with the interest rate on reserves now at 25 basis points. Puny, yes, but not compared to the yields on Treasury bills, federal funds, or checking accounts. And at that puny interest rate, banks are voluntarily holding about $1 trillion of excess reserves.

So the third easing option is to cut the interest rate on reserves in order to induce bankers to disgorge some of them. Unfortunately, going from 25 basis points to zero is not much. But why stop there? How about minus 25 basis points? That may sound crazy, but central bank balances can pay negative rates of interest. It’s happened.

Charging 25 basis points for storage should get banks sending money elsewhere. The question is where. If they just move money from their accounts at the Fed to the federal funds market, the funds rate will fall—but it can’t fall far. After all, it has averaged only 16 basis points since December 2008. If banks move the money into Treasury bills instead, the T-bill rate will fall. But even if it drops all the way to zero, that’s not a big change from its 12-month average of 11 basis points (for three-month bills). So charging 25 basis points is no panacea.

But suppose some fraction of the $1 trillion in excess reserves was to find its way into lending. Even if it’s only 10%, that would boost bank lending by 3%-4%. Better than nothing.

• A fourth way out. There is a fourth weapon, which the Fed chairman has not mentioned: easing up on healthy banks that are willing to make loans. Given bank examiners’ record of prior laxity, it is understandable that they have now turned into stern disciplinarians, scowling at any banker who makes a loan that might lose a nickel. That tough attitude keeps the banks safe, but it also starves the economy of credit.

Well, quite a few of those bank examiners happen to work for the Fed. It would probably do some good, maybe even a lot, if word came down from on high that some modest loan losses are not sinful, but rather a normal part of the lending business.

So that’s the menu. The Fed had better study it carefully, for if the economy doesn’t perk up, it will soon be time to fire the weak ammunition.