Overview
The Next Dollar Optimizer is built around two simple recurring investment decisions:
How far has my portfolio moved away from the mix I want?
And if I have money to invest today, where should it go?
The template uses Tiller Holdings data to calculate the portfolio’s current asset allocation, compare it with the user’s targets, identify underweight asset classes, and recommend how to distribute a new investment contribution.
The goal is simple: use new money to help move the portfolio toward its target allocation.
Make a copy: https://docs.google.com/spreadsheets/d/1CcYrvt8FjGGdTcACD4twg4Q-Qz3YNQwBmyvXolOaTFY/copy
The questions it answers
The Next Dollar Optimizer answers two related questions:
1. How far is my current portfolio from my target asset allocation?
2. Given that drift, where should my next investment contribution go?
Suppose the target portfolio is:
- U.S. Equity — 60%
- International Equity — 20%
- Bonds — 15%
- Cash — 5%
Markets move, so the portfolio will rarely remain exactly at those percentages. With money available to invest, the key questions are:
Which asset classes are underweight, how large are those gaps, and how should the contribution be allocated to move the portfolio closer to target?
The Next Dollar Optimizer calculates a recommended allocation automatically from the current holdings supplied by Tiller. By default, it spreads a new contribution across the asset classes that are below target based on the size of their funding gaps.
The optional Prioritize checkbox adds flexibility. Select a specific underweight asset class to see how directing new money there first would affect that deficit, with any remaining contribution distributed across the other underweight classes. This makes it easy to model questions like, “What happens if I prioritize Bonds with this contribution?” or “How much of this Cash shortfall could I close with my next contribution?”
That gives the user both a recommended starting point and the ability to model a more intentional contribution strategy.
For someone who contributes regularly to retirement or brokerage accounts, this can make each contribution part of the portfolio-rebalancing process.
How it works
The dashboard has two main sections.
Portfolio Allocation Drift Analysis
The first section groups securities from Tiller Holdings into six asset-class rows and compares the current portfolio with the user’s target allocation. The asset-class labels can be renamed or repurposed, and the framework can be expanded or simplified by updating the related ranges and classification choices.
The drift analysis shows where the portfolio currently sits relative to its target allocation and highlights the asset classes contributing most to the gap. Positive Funding Gap values indicate underweight allocations that need additional funding, while negative values indicate allocations above target.
The Portfolio Allocation vs Target Allocation chart compares Current Portfolio % with Target Portfolio %, making it easy to spot where the portfolio is over- or underweight.
Next Dollar Investment Planner
Enter the amount available to invest and the planner recalculates which underweight asset classes need funding. It recommends how to distribute the contribution and shows the resulting portfolio value and allocation after those dollars are invested.
By default, the contribution is distributed across underweight asset classes according to their relative funding needs. The optional Prioritize checkbox lets the user model funding one underweight asset class first and immediately see how that choice changes the recommended allocation and resulting portfolio.
The Next Dollar Investment vs Funding Gap chart compares each underweight asset class’s Funding Gap with the recommended Next Dollar Investment, showing how the proposed contribution addresses the portfolio’s current shortfalls.
Installation
1. Add Holdings through Tiller Investments
Use a Direct Fills Google Sheet. Connect your investment accounts through Tiller, link them to the spreadsheet, and install the Holdings sheet. Holdings data fills automatically as it becomes available. Refresh your investment accounts in Tiller if the Holdings data needs updating.
2. Copy the Next Dollar Optimizer tab
Use the Make a copy link to create your own copy of the template. In that copy, right-click the Next Dollar Optimizer tab, choose Copy to → Existing spreadsheet, and select the Direct Fills spreadsheet containing your Holdings data.
Dependencies and template location
The template is hosted in Google Sheets at the Make a copy link in this post. The only required dependent sheet is Holdings. Holdings History is not used by the optimizer.
Setup
Security Classifications
1. Classify your securities
Use the Security Classifications setup table to assign each security to an asset class.
- The optimizer matches each holding to the Security Classifications setup table using the security Description from Tiller Holdings. Enter each security description in the Description field and select its Asset Class. This supports holdings without ticker symbols, including proprietary retirement-plan funds.
- The Unmapped Holdings and Mappings Not in Holdings checks help identify securities that still need classification, holdings with unavailable descriptions, or saved mappings that no longer correspond to current Holdings data. Because holding descriptions can change when investment data is updated, these checks help surface classification maintenance before relying on the analysis or recommendation.
- The template starts with six asset-class rows. If the asset-class names are customized, keep the labels consistent across the drift analysis, investment planner, and Security Classifications dropdown choices. If rows are added or removed, update the related drift-analysis and planner ranges to match.
Portfolio Allocation Drift Analysis
1. Enter your target allocation
Enter the desired target percentage for each asset class. Each target must be between 0% and 100%, and the targets must total 100%. Asset classes outside the investment plan can remain at 0%.
Next Dollar Investment Planner
No additional one-time setup is required for the planner. It uses the same asset classes, security classifications, and target allocations configured above. The Contribution Amount and optional Prioritize selection are recurring inputs entered when you use the planner.
Usage
Use the optimizer whenever you want to review portfolio drift or decide how to allocate a new contribution.
Before relying on either section, review the Setup Health area and confirm the Holdings date is current enough for your decision. Refresh your investment accounts in Tiller if the data needs updating. If Setup Health shows a required validation failure, correct it before relying on the analysis or recommendation.
Portfolio Allocation Drift Analysis
1. Enter or review your target allocations
Confirm the target percentages for each asset class still reflect your intended portfolio. Update them if your allocation strategy has changed. Each target must remain between 0% and 100%, and the targets must total 100%.
2. Review allocation drift
Compare Current Portfolio % with Target Portfolio % for each asset class and review the Portfolio Allocation vs Target Allocation chart to see where the portfolio has moved away from target.
3. Review funding gaps
Review Funding Gap and the summary metrics to identify the largest underweight allocations. Positive Funding Gap values indicate asset classes that need additional funding, while negative values indicate allocations above target.
Next Dollar Investment Planner
1. Enter your contribution
Enter a positive amount currently available to invest. The funding gaps and recommended allocation recalculate automatically.
2. Optional: prioritize an asset class
Select one Prioritize checkbox to model funding a specific underweight asset class first. Any remaining contribution is then distributed among the other underweight classes. Only one asset class can be prioritized at a time.
3. Review the recommendation
Review Invest Next $, Resulting $, and Resulting % before placing any trades.
Built-in checks
Potential data, setup, and input issues are surfaced clearly before someone relies on the analysis or recommendation. The checks cover four areas: Holdings data, Security Classifications, Portfolio Allocation Drift Analysis, and the Next Dollar Investment Planner.
Holdings data
- No investment holdings found
- Potentially stale Holdings data
The dashboard displays the latest Holdings date so the user can see when the underlying investment data may need to be refreshed.
Security Classifications
- Unmapped holdings
- Duplicate descriptions in the Security Classifications setup table
- Saved mappings that no longer correspond to current holdings
Portfolio Allocation Drift Analysis
- Missing or invalid target allocations, or targets that do not total 100%
Next Dollar Investment Planner
- Missing or invalid contribution amounts
- Multiple Prioritize selections
Stale Holdings data is surfaced as a warning. Required setup or input validation failures should be corrected before relying on the analysis or recommendation; investment recommendations are suppressed until corrected.
How the recommendation is calculated
For each asset class, the planner first calculates its target dollar value after the proposed contribution:
Target % × (Current Portfolio Value + Contribution)
It then compares that target value with the class’s current value.
Only asset classes with positive funding needs are eligible to receive a recommended contribution.
Holdings values, security classifications, target allocations, priority selections, and the contribution amount can all change the recommendation automatically.
How it uses Tiller Investments
The optimizer reads directly from the Holdings sheet populated by Tiller Investments.
Its formulas use open-ended Holdings ranges so newly populated holdings are incorporated automatically. Security classifications are maintained separately from the Tiller source data, and previously unseen securities are surfaced through the built-in checks.
The dashboard and charts update as the underlying Holdings data changes.
Everything is built with native Google Sheets formulas, checkboxes, conditional formatting, data validation, and charts. No Apps Script or third-party service is required.
Permissions
You’re welcome to copy, use, and modify this template for your own workflow.
Notes
- The optimizer assumes the standard Tiller Holdings column layout. It uses open-ended row ranges, so new holdings are incorporated automatically, but substantially rearranging the Holdings columns may require formula updates.
- Holdings data availability and completeness can vary by financial institution and data provider. The optimizer can only analyze holdings that are available in the Tiller Holdings sheet.
- The template is focused specifically on asset-allocation drift and new contributions.
- It does not model individual security selection, expected returns, tax lots, wash sales, account-specific tax treatment, trading costs, or asset location.
- The output is a planning aid and is not investment, tax, or financial advice.
FAQ
Do I need ticker symbols?
No. The optimizer maps holdings using the security Description from Tiller Holdings, so it can support funds without ticker symbols.
What happens when a new holding appears?
The Unmapped Holdings check surfaces it until you add its description and asset class to Security Classifications.
Can I rename or change the asset classes?
Yes. Keep the labels consistent across the drift analysis, planner, and classification dropdowns. If you add or remove asset-class rows, update the related ranges.
Can I prioritize more than one asset class?
No. Select at most one Prioritize checkbox. If more than one is selected, recommendations are suppressed until the selection is corrected.
Does the template place trades?
No. It is a planning tool only. It calculates a suggested allocation for the contribution; you decide whether and how to execute any trades.
Does it require Apps Script?
No. It uses native Google Sheets formulas, checkboxes, conditional formatting, data validation, and charts.