How to ensure non-negative nominal interest on your cash

John Cochrane writes:

So, quiz question for your economic classes: Suppose we have substantially negative interest rates — -5% or -10%, say, and lasting a while. But there is no currency. How else can you ensure yourself a zero riskless nominal return?

Here are the ones I can think of:

• Prepay taxes. The IRS allows you to pay as much as you want now, against future taxes.
• Gift cards. At a negative 10% rate, I can invest in about $10,000 of Peets’ coffee cards alone. There is now apparently a hot secondary market in gift cards, so large values and resale could take off.
• Likewise, stored value cards, subway cards, stamps. Subway cards are anonymous so you could resell them.
• Prepay bills. Send $10,000 to the gas company, electric company, phone company.
• Prepay rent or mortgage payments.
• Businesses: prepay suppliers and leases. Prepay wages, or at least pre-fund benefits that workers must stay employed to earn.

Comments section: how many more can you think of?

His conclusion:

The zero bound is not just cash.

More generally, he is discussing work by Kenneth Rogoff.