Yield Restriction on Bond Proceeds: What It Is and When It Applies

Yield restriction is the federal arbitrage rule that limits the yield an issuer may earn on invested tax-exempt bond proceeds to the yield on its bonds, plus a tolerance the regulations set by investment class, and it applies to proceeds once their temporary period ends, other than amounts in a reasonably required reserve fund or the minor portion.

The consequence of getting it wrong comes from the Code itself: section 148(a) treats a bond as an arbitrage bond when proceeds of its issue are reasonably expected at issuance to be used to acquire higher yielding investments or to replace funds used to acquire them, or are intentionally used that way, and section 103(b)(2) denies arbitrage bonds the gross income exclusion that section 103(a) gives interest on state and local bonds.

Yield restriction and rebate are the two halves of the federal arbitrage rules for bond proceeds, and an issue has to satisfy both sets of rules.

What is yield restriction?

Yield restriction is the requirement, under the section 148 arbitrage rules, that an issuer not invest gross proceeds of its bonds at a yield materially higher than the yield on the bonds, outside the exceptions the rules provide.

Section 148(a) of the Internal Revenue Code defines an arbitrage bond by expectations and intent at issuance: a bond is an arbitrage bond if any portion of its issue's proceeds are reasonably expected, at the time of issuance, to be used to acquire higher yielding investments or to replace funds used to acquire them, and intentional use of proceeds that way is treated the same.

Section 103(a) excludes interest on state and local bonds from gross income, and section 103(b)(2) provides that the exclusion does not apply to any arbitrage bond.

Earning a higher yield is not by itself disqualifying: the rules permit it during temporary periods, in a reasonably required reserve fund, and in the minor portion of an issue, so the analysis turns on whether a particular use fits one of those allowances.

IRS Publication 5271, the IRS's overview of the arbitrage requirements, which states on its face that it is not formal guidance, makes the structure explicit: bonds that are arbitrage bonds under either set of rules are arbitrage bonds even if they are not arbitrage bonds under the other set.

The tolerance the restriction actually gives depends on the class of investment, under Treasury Regulation §1.148-2(d)(2).

For yield restriction purposes, Treasury Regulation §1.148-5(b)(2)(i) computes yield separately for each class of investments and does not blend yields across classes, and §1.148-5(d)(2) generally requires yield-restricted nonpurpose investments to be valued at present value.

When does yield restriction begin?

Yield restriction begins for proceeds when their temporary period runs out, and the periods available depend on what the proceeds are for.

Section 148(c)(1) of the Code is the statutory basis: a bond is not treated as an arbitrage bond solely because proceeds may be invested in higher yielding investments for a reasonable temporary period until they are needed.

For example, capital project proceeds get a 3-year temporary period from the issue date under Treasury Regulation §1.148-2(e)(2)(i) only if the issuer reasonably expects to satisfy the expenditure test, the time test and the due diligence test, while gross proceeds not otherwise eligible get 30 days from receipt under §1.148-2(e)(7).

The temporary periods page sets out each period, its tests and its conditions in full.

When a period ends, proceeds still unspent become subject to yield restriction, and Treasury Regulation §1.148-5(b)(3) allows investments held past a temporary period to be treated as purchased at fair market value at the end of the period for yield restriction purposes.

The small issuer exception does not change the analysis: IRS Publication 4079 notes that it is an exception from rebate and not from the arbitrage rules altogether, so a qualifying small issuer still needs a temporary period for project funds and must be able to show that any reserve fund is reasonably required.

Nor does a temporary period settle the rebate question, because Publication 5271 notes that the yield restriction rules may allow the issuer to earn the arbitrage while the rebate rules may not allow the issuer to keep it.

Restricting proceeds: SLGS and the materially higher yield limits

Treasury offers nonmarketable State and Local Government Series (SLGS) securities so issuers of tax-advantaged bonds have investments that help them comply with the Internal Revenue Code, under 31 CFR 344.0(a).

The SLGS rate is the current Treasury borrowing rate less one basis point, floored at zero under 31 CFR 344.1, and Treasury determines that borrowing rate, and may use proxies for maturities it does not issue, rather than taking it from a published market yield.

Because yield is computed separately for each class under Treasury Regulation §1.148-5(b)(2)(i), the restriction is measured class by class rather than across a fund as a whole.

For proceeds with term remaining to invest, our GIC or SLGS comparison takes up the choice between a competitively bid investment agreement and a SLGS subscription.

Buying within the limit is one route to restriction, and the regulations also provide a payment route, which is where yield reduction payments come in.

How does a yield reduction payment satisfy yield restriction?

Under Treasury Regulation §1.148-5(c)(1), a yield reduction payment is an amount paid to the United States that is treated as a payment for the investment reducing its yield, which lets an issuer satisfy yield restriction without restricting the actual investment rate.

The route is category-specific: §1.148-5(c)(3) includes nonpurpose investments of proceeds that qualified for the capital project, working capital, pooled financing or investment-proceeds temporary periods, certain variable-yield issues, certain transferred proceeds, reserve funds up to 15 percent of stated principal, and investments made when SLGS sales are suspended, among other listed cases.

They are not available for everything: the paragraph generally excludes gross proceeds of advance refunding issues except as expressly provided, and the Form 8038-T instructions point issuers with ineligible excess yield, such as an incorrectly invested advance refunding escrow, to the IRS's VCAP closing agreement process.

The payment then flows into the rebate arithmetic: Treasury Regulation §1.148-3(d)(1) counts yield reduction payments among an issue's payments, alongside amounts paid to buy nonpurpose investments, the value of investments first allocated to the issue, and any computation credit.

Payment goes to the United States on Form 8038-T, which the instructions say issuers of bonds subject to section 148 must use to make arbitrage rebate and related payments, including yield reduction payments, the penalty in lieu of rebate, and late-payment penalties and interest, with a separate form for each issue.

The same form asks whether proceeds were invested in a guaranteed investment contract, with the provider's name and term to the nearest tenth of a year (line 30), whether proceeds were invested beyond the temporary periods (line 31), and who prepared the calculations (line 32).

When a yield reduction payment is available, and how the amount is computed and timed, are the subject of our yield reduction payments page.

How do issuers plan for yield restriction at issuance?

The restriction an issue will carry is set largely at issuance, because the expected use of proceeds fixes the temporary periods and waivers of the temporary period and reserve fund allowances must be elected on or before the issue date.

Treasury Regulation §1.148-2(h) lets an issuer elect, on or before the issue date, to waive the right to invest in higher yielding investments during any temporary period or as part of a reasonably required reserve fund, and it may waive the minor portion at any time.

Whether a waiver fits a given issue is a determination for bond counsel and tax counsel.

Spending pace belongs in the same planning conversation: the 18-month spending exception in Treasury Regulation §1.148-7(d)(1) requires at least 15 percent of gross proceeds spent within 6 months, at least 60 percent within 12 months and 100 percent within 18 months, and it is available only where all gross proceeds qualify for the 3-year capital project temporary period.

The 18-month exception is an exception to the rebate requirement, and section 148 tests an issue against both sets of rules independently, so meeting that spending schedule does not substitute for a temporary period on the yield restriction side.

Conduit issuers carry one more planning item: IRS Publication 5005 notes that fees charged by the conduit issuer can raise the effective yield on a conduit loan, which is a purpose investment, and that conduit issuers generally must ensure the loan yield does not exceed the bond yield by more than the permitted spread.

For an issue already closed, an independent Bidding Agent or reinvestment advisor can check your proceeds against the rules before the next rebate computation date or Form 8038-T filing.

mGIC is an independent, SEC-registered municipal advisor and Bidding Agent paid by the winning provider, and it offers a free, no-obligation reinvestment review that looks at fund objectives, permitted investments, draw schedules, credit terms and timing.

Which temporary periods, limits and exceptions apply to a particular issue is a legal and tax determination that belongs to bond counsel and tax counsel.

Last updated 2026-10-06.

This page is general educational information about municipal finance and federal and state rules as of the date shown. It is not legal, tax or investment advice, and it is not a recommendation about any particular investment. Product availability, legality and suitability depend on the issuer, jurisdiction, governing documents and transaction-specific facts. Final legal and tax determinations remain with the issuer's bond counsel, tax counsel and other advisors.