PortfolioIQ: Multi-Account Holdings Tracker & Rebalance Planner

Problem and target customer

Why this exists

Customer problem

Investors managing several brokerage accounts track holdings in disconnected spreadsheets, manually calculate allocation drift, and construct rebalancing trades by hand—a process that is error-prone and time-consuming for portfolios with 20+ positions.

Who pays

Self-directed investors and independent wealth advisors managing 2–10 brokerage accounts who need a focused rebalancing workflow without enterprise portfolio management software.

Business model

Monthly subscription with a paid workspace tier for users managing multiple accounts and target allocation models.

Editorial note

PortfolioIQ targets a specific pain point: investors with multiple brokerage accounts who manually reconcile holdings and calculate rebalancing trades in spreadsheets. The MVP keeps scope tight—CSV import, target allocation models, drift visualization, and a trade plan export—so a user can move from scattered positions to an actionable rebalance plan in one sitting.

The rebalance engine compares each holding's current weight against the target allocation model and computes the minimum set of trades to bring drift within a user-defined tolerance. By excluding direct brokerage connections and automated execution, the MVP avoids regulatory complexity and focuses on the planning workflow where the value is clearest.

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Review MVP scope, workflow, states, data rules, architecture, and acceptance criteria.

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Evaluation preview

What would it take to run?

Directional infrastructure estimates for the current 1,000 generated outputs assumption. Open the full calculator when you are ready to change it.

Open full cost and deployment

ManagedSelected

$30-$90/ month

Managed app hosting, database, backups, and basic observability for the ai-generation workflow.

Lowest operating effort

Lean self-hosted

$13-$53/ month

One small VPS running the app, database, media volume, and backup job.

Lowest baseline cost

More control

$50-$150/ month

Separate app, data, storage, and worker capacity for cleaner operations.

Most separation and control

Build blueprint

Build the first paid use case

Product goal

Who it serves and what it must change

Target user: Self-directed investor managing 3+ brokerage accounts with 20+ total holdings who currently tracks allocation in spreadsheets.
Problem: Reconciling holdings across accounts and calculating rebalancing trades manually is slow and error-prone, with no single view of portfolio drift.
Measurable outcome: User imports all positions, sets a target allocation, and receives a complete rebalance trade plan within 15 minutes of first use.

MVP scope

What ships now and what waits

Included

CSV import and manual entry of holdings per account
Asset-class mapping per holding
Target allocation model builder
Current vs. target allocation drift visualization
Rebalance trade plan generation with buy and sell quantities
CSV and PDF export of trade plan

Excluded

Direct brokerage API connections
Automated trade execution
Real-time price streaming
Tax-lot optimization
LLM-generated advice

UX and user flow

Screens, actions, and states

Holdings Import

Upload CSV or manually enter positions with ticker, shares, cost basis, and account selection.

Upload CSVAdd holding manuallyValidate fieldsFlag duplicates

Allocation Model Builder

Create and edit target allocation models with asset-class percentages summing to 100.

Add asset classSet target percentageValidate sum equals 100Save model

Allocation Dashboard

Display current allocation vs. target with drift metrics and charts.

View donut chartView bar chart comparisonSee drift per asset classSelect active target model

Rebalance Trade Plan

Show computed buy and sell quantities per holding to reach target allocation.

Review trade tableAdjust tolerance thresholdRegenerate planExport CSV or PDF

Primary flow

Import holdings via CSV or manual entry
Map holdings to asset classes
Create or select a target allocation model
Review allocation drift on dashboard
Generate and export rebalance trade plan

Loading, empty, and error states

No holdings imported—empty dashboard with import prompt
Holdings imported but no target model—prompt to create allocation model
Target model set with drift within tolerance—green status, no trades needed
Target model set with drift exceeding tolerance—amber status, trade plan generated

Core entity outline

Entities and business rules

Account

Represents a brokerage account holding positions.

Fields: id, user_id, name, institution, currency
Relations: has many Holdings

Holding

A single position within an account.

Fields: id, account_id, ticker, asset_class, shares, cost_basis, price_cached
Relations: belongs to Account, belongs to AssetClass

AllocationModel

User-defined target allocation with percentages per asset class.

Fields: id, user_id, name, tolerance_percent, created_at
Relations: has many AllocationTargets

RebalancePlan

Generated set of trades to align current allocation with target model.

Fields: id, user_id, allocation_model_id, status, generated_at, total_trades
Relations: belongs to AllocationModel, has many TradeItems

Business rules

Allocation model target percentages must sum to exactly 100.
Each holding must map to exactly one asset class before drift can be calculated.
Rebalance trade quantities are rounded to whole shares for equities.
Trade plan status transitions: draft → generated → exported.
Drift exceeding the model's tolerance threshold triggers trade plan generation.

Architecture and data flow

Components, integrations, and controls

CSV Import Service

Parses uploaded CSV files, validates required fields, and creates Holding records.

Allocation Engine

Calculates current allocation by asset class and computes drift against the active target model.

Rebalance Calculator

Generates buy and sell trade quantities per holding to bring drift within tolerance.

Export Service

Renders trade plan as CSV or PDF for download.

Integrations

Market data API (end-of-day prices) via optional Make scenario to populate PriceCache
CSV file upload from user's local machine

Data flow

User uploads CSV → CSV Import Service validates and creates Holdings → Allocation Engine computes current weights → User selects target model → Rebalance Calculator generates TradeItems → Export Service produces CSV or PDF

Failure handling

CSV with missing ticker or shares columns returns row-level validation errors without importing partial data
Allocation model with percentages not summing to 100 blocks save and shows the delta
PriceCache miss for a holding uses last known cost basis and flags the holding as stale
Rebalance calculation with insufficient cash for buy trades marks trades as unfunded

Security

User authentication required for all portfolio data access
Holdings and trade plans scoped to authenticated user_id
CSV uploads validated for file type and row count limits

Rate limits

CSV import limited to 500 rows per upload
Maximum 10 allocation models per user in the base tier

Deliverables and acceptance

Definition of done for the MVP

Deliverables

Desktop-first web app with holdings import, allocation dashboard, and trade plan views
PostgreSQL schema for accounts, holdings, allocation models, and rebalance plans
Rebalance calculation API with drift and trade generation endpoints
CSV and PDF export of rebalance trade plans

Acceptance criteria

Given a CSV with 20 holdings across 3 accounts, the system imports all positions and displays correct share counts within 30 seconds.
Given a target allocation model with 60% equities and 40% fixed income, the dashboard shows current allocation drift accurate to within 0.1%.
Given drift exceeding the 5% tolerance threshold, the rebalance plan lists specific buy and sell quantities per holding that would bring allocation within tolerance.
Given a generated trade plan, the user can export it as a CSV file containing ticker, action, shares, and estimated value columns.
Given an allocation model where percentages sum to 95, the system blocks save and displays the 5% shortfall.

Recommended stack

Enough technology for the first version

Frontend

Lovable

Rapid build of the desktop-first finance dashboard with allocation charts and trade plan tables.

Database

PostgreSQL on Railway

Durable storage for holdings, allocation models, and rebalance plans with relational integrity across accounts.

Backend API

Railway Node service

Hosts the rebalance calculation engine and CSV import processing endpoints.

Charts

Recharts

Renders donut and bar charts for current vs. target allocation comparison.

Automation

Make

Optional scheduled job to refresh cached prices from a market data API and notify users of significant drift.

Why this is sufficient

The MVP centers on data import, allocation math, and trade-plan generation—all of which need a relational database and a calculation backend. Lovable handles the chart-heavy desktop UI, Railway hosts the database and API, and Make provides optional price-refresh glue without building a full market data pipeline.

Not required for the MVP

Maps API integrationLLM API integrationReal-time market data streamingMobile-responsive layoutMulti-user collaboration

Next stepTurn the blueprint into an execution plan

Copy the build prompt, model the operating cost, and choose where to deploy.

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Execution

Build, price, and deploy the MVP

Once the blueprint is clear, use the prompt, cost model, and deployment options to start building.

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Cost calculator

Model the MVP operating cost

A technical run-cost estimate for the first production version. Team, acquisition, payment fees, and business COGS are excluded.

Estimated monthly total$30-$90

$15-$45 per 500 generated outputs

Generated outputs / month1,000 generated outputs

Selected pathEasiest

Pricing checkedAug 2, 2026

Cost breakdown

$30-$90 per month

Low and high values allow for usage variance and plan headroom.

Managed infrastructure

Managed app hosting, database, backups, and basic observability for the ai-generation workflow.

50K generated outputs included, then $8-$20 per 100K generated outputs

$25-$65

Maps API

Maps API is implied by the source workflow or feature list.

1K generated outputs included

Object storage

Uploaded files or generated assets need durable media storage.

Monthly allowance from this idea's operating profile

$5-$25

Included

Application hosting
Relational database
Basic backups
property concepts, approvals, and buyer inquiries state
Maps API
Object storage

Not included

Paid acquisition
Founder or team time
Tax or legal review
Custom enterprise procurement

Pricing basis

The estimate combines the selected infrastructure path, required operating modules, selected optional modules, and usage above included monthly allowances. Taxes and regional uplifts are excluded.

Managed app baseline Google Maps Platform pricing Amazon S3 pricing

Deployment options

Pick the operational tradeoff

Choose based on operating preference, not only the headline price.

EasiestRecommended

Railway

Fast Docker deployment for the app, database, worker, and preview workflow without managing a VPS.

$15-90/month before usage-heavy add-ons

Good fit

Fast setup
Low starting cost
Good preview workflow

Limitation

Usage billing needs active monitoring as traffic and jobs grow.

Open Railway

Cheapest

Vultr

Run the app, worker, and database on one small Vultr VPS with Docker Compose and explicit backups.

$8-60/month before managed add-ons

Good fit

Predictable baseline
Portable setup
Room for workers

Limitation

You own patching, backups, monitoring, and incident response.

Deploy on Vultr View the lean VPS guide

More control

DigitalOcean

Separate application, worker, data, storage, and backup responsibilities as the workload grows.

$10-120/month before managed add-ons

Good fit

Cloud VPS control
Global regions
Room for workers

Limitation

You own server setup, patching, backups, and operational monitoring.

Explore DigitalOcean View the separated cloud guide

Start building

Prototype, automate, then deploy

Recommended route

01Vibe-coding builderBuild Portfolio Dashboard UI

Create the desktop-first dashboard with holdings import form, allocation donut and bar charts, drift metric cards, and the rebalance trade plan table.

Open Lovable 02AutomationOptional Price Refresh Scenario

Configure a scheduled Make scenario that fetches end-of-day prices from a market data API and updates the PriceCache table, then triggers a drift notification email if any asset class exceeds tolerance.

Open Make 03DeployDeploy Database and Rebalance API

Provision PostgreSQL for holdings, allocation models, and rebalance plans; deploy a Node service exposing CSV import, allocation calculation, and trade-plan generation endpoints.

Open Railway

PortfolioIQ: Multi-Account Holdings Tracker & Rebalance Planner

Is this worth validating?

Build this if

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Validate first

Why this exists

Customer problem

Who pays

Business model

What do you need next?

What would it take to run?

Build the first paid use case

Who it serves and what it must change

What ships now and what waits

Included

Excluded

Screens, actions, and states

Primary flow

Loading, empty, and error states

Entities and business rules

Business rules

Components, integrations, and controls

Integrations

Data flow

Failure handling

Security

Rate limits

Definition of done for the MVP

Deliverables

Acceptance criteria

Enough technology for the first version

Lovable

PostgreSQL on Railway

Railway Node service

Recharts

Make

Why this is sufficient

Not required for the MVP

Build, price, and deploy the MVP

Copy this into a builder

Your build prompt is ready

Model the MVP operating cost

Usage assumptions

$30-$90 per month

Included

Not included

Pricing basis

Pick the operational tradeoff

Railway

Good fit

Limitation

Vultr

Good fit

Limitation

DigitalOcean

Good fit

Limitation

Prototype, automate, then deploy

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