5/6 ARM

Hybrid mortgage with a five-year fixed rate followed by six-month adjustment opportunities.

A 5/6 ARM is a hybrid adjustable-rate mortgage whose interest rate is fixed for five years and can generally adjust every six months afterward. The product may also be written as a 5/6-month ARM or 5/6m ARM to make the second interval explicit.

How to Read the 5/6 Label

PartMeaning
5Initial rate is fixed for five years
6First post-introductory adjustment interval is six months

The two numbers describe timing. They do not state the index, margin, caps, floor, or maximum payment. The note and ARM rider supply those controlling terms.

Why It Matters

The 5/6 ARM can be mistaken for a 5/1 ARM because both begin with five fixed years. The difference appears after the initial period: the 5/6 structure has another adjustment opportunity six months after a reset, while the 5/1 structure generally waits a year.

More frequent adjustment opportunities can pass market-rate changes through to the note rate sooner. That can work in either direction, subject to the contract. If the index rises, the loan may face another increase sooner; if the index falls, it may also reach another possible decrease sooner. Caps, a floor, and rounding rules can limit either result.

Frequency is only half of the comparison. A six-month ARM may use a smaller periodic cap than an annually adjusting ARM. Borrowers should compare how often the rate can change and how much it can change at each event.

Where It Appears in the Borrower Process

Borrowers encounter the 5/6 label in rate quotes, ARM program disclosures, and the Loan Estimate. Before closing, the borrower should locate these items in the lender’s documents:

  • exact end date of the five-year fixed period
  • index and the date used to select its value
  • margin added to the index
  • initial adjustment cap
  • six-month periodic adjustment cap
  • lifetime maximum and any floor
  • date the adjusted payment first becomes due

The first reset does not necessarily equal the index-plus-margin result. The Initial Adjustment Cap may limit the move from the opening rate. Later resets use the periodic cap and remain subject to the lifetime limits.

Practical Example

A borrower closes a 5/6 ARM with a 5.00% initial rate. At the first adjustment, the index-plus-margin calculation supports 7.50%, but the initial cap permits no more than a 2-percentage-point increase. The new rate cannot exceed 7.00% at that reset, subject to all other contract terms.

Six months later, the loan becomes eligible for another review. The index may be different, and the periodic cap now controls the maximum step from the current rate. The example shows why a borrower cannot forecast the second reset using the initial cap alone.

5/6 ARM Compared With 5/1 ARM

Feature5/6 ARM5/1 ARM
Initial fixed periodFive yearsFive years
Later adjustment intervalSix monthsOne year
Frequency after first resetPotentially twice per yearPotentially once per year
Size of each changeDetermined by capsDetermined by caps

Neither label identifies the better loan. The starting rate, closing costs, index, margin, caps, floor, and expected time in the mortgage all matter.

How It Differs From Nearby Terms

A 5/6 ARM is a specific Hybrid ARM, while hybrid ARM is the broader structure with a fixed phase followed by an adjustable phase.

It differs from ARM Adjustment Period because the adjustment period is one timing feature. The 5/6 label combines that feature with the five-year initial fixed period.

It differs from an ARM Reset because a reset is one calculation event. Six months describes the interval between eligible events after the fixed period.

Knowledge Check

  1. What does the 6 in 5/6 ARM describe? It describes a six-month first post-introductory adjustment interval, not a six-year period.
  2. Does adjusting every six months mean the rate must change twice a year? No. It means the loan is eligible for a reset; the formula may produce an increase, decrease, or no change.
  3. Why must adjustment frequency and periodic caps be compared together? Frequency controls when changes can occur, while the cap controls the size of each permitted change.
Revised on Sunday, August 30, 2026