Skip to content
English
Go to www.timelineapp.co
  • There are no suggestions because the search field is empty.

Withdrawal rules - Guardrail | Timeline Help Centre

Summary

  • The guardrail strategy consists of two rules: the Capital Preservation Rule and the Prosperity Rule.

  • It enables dynamic spending adjustments based on portfolio performance.

  • Withdrawals increase or decrease depending on how the current withdrawal rate compares to the initial rate.

  • The threshold (X%) and adjustment amount (Y%) for both rules can be customised.

Description

The guardrail strategy was created by financial planner Jonathan Guyton and later refined with William Klinger. It is a dynamic retirement income approach that adjusts withdrawals using predefined rules rather than relying on a fixed inflation-linked increase each year.

Instead of asking, “Can I always increase spending with inflation?”, the guardrail framework asks:

Is the portfolio performing strongly enough to justify an increase?
Or weak enough to require a reduction?

The strategy revolves around two key rules:

Capital Preservation Rule

This rule is designed to protect the portfolio during downturns.

It is triggered when the current withdrawal rate increases by more than X% above the initial withdrawal rate.

When triggered:

  • The withdrawal amount is reduced by Y%.

This prevents spending from drifting too high relative to the remaining portfolio value after market declines.

Prosperity Rule

This rule allows retirees to benefit from strong portfolio growth.

It is triggered when the current withdrawal rate decreases by more than X% below the initial withdrawal rate.

When triggered:

  • The withdrawal amount is increased by Y%.

This allows retirees to enjoy higher income when portfolio performance has materially improved sustainability.

Both the X% threshold and the Y% adjustment can be modified to reflect a client’s:

  • Risk tolerance

  • Desire for income stability

  • Flexibility in spending

  • Legacy objectives

Example

Assume a retiree begins with:

  • Portfolio value: £1,000,000

  • Initial withdrawal: £40,000

  • Initial withdrawal rate: 4%

Let’s assume the guardrails are set at:

  • 20% threshold

  • 10% adjustment

Year 4 – Strong Portfolio Growth

By year four:

  • The portfolio has grown to £1,400,000.

  • Due to inflation adjustments, the withdrawal is now £45,000.

The current withdrawal rate is:

£45,000 ÷ £1,400,000 = 3.2%

This is more than 20% lower than the initial 4% rate.

The Prosperity Rule is triggered.

The withdrawal increases by 10%:

£45,000 → £49,500

The retiree benefits from strong performance while remaining within a structured framework.

Year 7 – Market Decline

By year seven:

  • The portfolio has fallen to £900,000.

  • The retiree is withdrawing £50,000 (due to inflation and prior increases).

The current withdrawal rate is:

£50,000 ÷ £900,000 = 5.5%

This is more than 20% above the initial 4% rate.

The Capital Preservation Rule is triggered.

The withdrawal is reduced by 10%:

£50,000 → £45,000

This reduction helps protect the remaining capital and improves long-term sustainability.

Conclusion

The guardrail strategy provides a structured, rules-based way to adjust retirement income dynamically.

By combining:

  • The Capital Preservation Rule (protecting against downturns)

  • The Prosperity Rule (allowing income growth in strong markets)

retirees can balance sustainability with flexibility.

Because both the threshold (X%) and adjustment size (Y%) are configurable, the strategy can be tailored to suit different client preferences — from stability-focused retirees to those comfortable with more income variability.