Montana TRS · Glossary

Montana TRS words, in plain English

The terms you'll see in letters from the Montana Teachers' Retirement System (Montana TRS), on its fact sheets and on this site, each in a sentence, with its source.

These are the words you'll meet in Montana TRS letters and fact sheets, in My TRS and on these pages. To put them to work, try the Montana TRS calculator, or start with Tier One or Tier Two and the formula.

Accumulated contributions

The money taken from your pay or paid by you into your Montana TRS account, plus interest.

Montana TRS web page: Glossary of Terms

Actuarial equivalent

A benefit of equal value, figured with the mortality table and interest rate the retirement board sets.

Montana TRS web page: Glossary of TermsMore on this →

Average final compensation (AFC)

The average of your highest 3 (Tier One) or 5 (Tier Two) consecutive fiscal years of pay.

MCA 19-20-805More on this →

Beneficiary

A person you name to receive a payment when you die, other than a joint annuitant.

Montana TRS web page: Glossary of TermsMore on this →

Break in service

The 120 days after your last day when you can't do Montana TRS-reportable work.

MCA 19-20-734More on this →

Cost basis

The contributions in your account that you've already paid tax on.

Montana TRS web page: Glossary of TermsMore on this →

Cost-of-living adjustment

Montana TRS doesn't have one tied to inflation; its yearly raise is the GABA, set in law.

Montana TRS web page: What is GABAMore on this →

Creditable service

Years and part-years credited to you, by fiscal year (July 1-June 30), no more than one year per fiscal year.

MCA 19-20-401(6), (9)More on this →

Effective retirement date

The first of the month after you terminate employment to retire.

Montana TRS web page: Glossary of TermsMore on this →

Fiscal year

July 1 through June 30, the year Montana TRS counts service by.

Montana TRS web page: Glossary of Terms

Full-time service

At least 180 days in a fiscal year, at least 140 hours a month for 9 months, or 1,080 hours under an alternative school calendar.

Montana TRS web page: Glossary of TermsMore on this →

GABA (Guaranteed Annual Benefit Adjustment)

Montana TRS's yearly January raise, set in law rather than tied to inflation.

Montana TRS web page: What is GABAMore on this →

Inactive member

A vested or non-vested member who no longer works in a Montana TRS-reportable position.

Montana TRS web page: Glossary of Terms

Joint annuitant

The one person you name under Option A, B or C to keep receiving a benefit after you die.

MCA 19-20-702(2); Montana TRS web page: Benefit PaymentsMore on this →

Membership service

Service you actually worked in a Montana TRS-reportable position, not service bought or awarded for time you didn't work.

Montana TRS web page: Glossary of TermsMore on this →

Montana TRS

The Montana Teachers' Retirement System, Helena. Phone 406-444-3134 or toll-free 866-600-4045.

Working After Retirement fact sheet (Mar. 26, 2026), p. 5More on this →

Normal Form

The life-only allowance with the largest monthly payment.

MCA 19-20-702(1); Actuarial Valuation (July 1, 2025), p. 47More on this →

Normal retirement age

An age no earlier than 60.

Montana TRS web page: Glossary of Terms

Pre-arranged agreement

An oral or written agreement, made before you retire, to work for the employer again in any capacity, including as a contractor or volunteer.

Montana TRS web page: Glossary of TermsMore on this →

Suspension of benefits

If a retiree returns to covered work and becomes an active contributing member, benefits generally stop until they leave all Montana TRS-reportable work and apply to restart them. Some exceptions apply.

Montana TRS web page: Glossary of TermsMore on this →

Termination date

The last day you worked in a Montana TRS-reportable position.

Montana TRS web page: Glossary of Terms

Termination pay

Lump-sum leave payouts, severance and retirement incentives paid when you leave, which you may add to your AFC.

MCA 19-20-101(32); Termination Pay fact sheet (Mar. 26, 2026), p. 1More on this →

Tier One / Tier Two

Montana TRS members who joined before / on or after July 1, 2013.

MCA 19-20-101(33)-(34)More on this →

Vested

Having 5 full years of membership service, which gives you a right to a future benefit.

MCA 19-20-101(35)More on this →

Source: Montana TRS: Understand Your Benefits (web page) and fact sheets, Fetched Nov. 12, 2026; fact sheets revised 2019-2026, fact sheets: Termination Pay p. 1; Working After Retirement p. 5. Also: Montana TRS web pages: Glossary of Terms, What is GABA, Benefit Payments; Actuarial Valuation (July 1, 2025); MCA §§ 19-20-101, 19-20-401, 19-20-702, 19-20-734, 19-20-805. Last reviewed .