A

Stock Gains Tax Auto-Calculator

4.05

Derivation Chain

Step 1 Stock market surge + large-scale profit realization
→
Step 2 Capital gains tax and comprehensive financial income tax filing demand
→
Step 3 Automated stock tax calculation and optimization simulation for individual investors

Competitor references

No usable source links are available for this idea. Its signal notes and scores need independent verification.

Problem

With KOSPI surpassing 6,300, major shareholders (holding $740,000+ per stock) and overseas stock investors must file capital gains tax, while those exceeding $15,000 in financial income face comprehensive taxation. Manually consolidating trade records across 3–4 brokerages and calculating taxes takes an average of 4–8 hours. Hiring a tax accountant costs $220–$740 per case, and investors who miss tax optimization strategies (staggered selling, loss offsetting, etc.) overpay an estimated $370–$1,500 on average.

Solution

Users upload trade history exported as Excel/CSV from brokerage MTS/HTS platforms. The system auto-calculates capital gains tax and comprehensive financial income tax, then simulates tax differences across optimization scenarios including staggered selling, loss offsetting, and spousal gift-then-sell strategies. Includes filing deadline reminders and auto-generated HomeTax (Korean IRS) return drafts.

Target: Individual investors aged 30–60 with $74,000+ in investments using 2+ brokerages, especially overseas stock investors
Revenue Model: Basic calculation Free, Premium (tax optimization simulation + return generation) at $36/account/year, tax accountant referral fee at $37 Per Transaction
Ecosystem Role: Infrastructure
MVP Estimate: 2_weeks

NUMR-V Scores

N Novelty
2.0/5
U Urgency
5.0/5
M Market
5.0/5
R Realizability
4.0/5
V Validation
4.0/5
NUMR-V Scoring System
N Novelty1-5How uncommon the service is in market context.
U Urgency1-5How urgently users need this problem solved now.
M Market1-5Market size and growth potential from proxy indicators.
R Realizability1-5Buildability for a small team with realistic constraints.
V Validation1-5Validation signal quality from competition and demand data.
Each dimension is scored 1-5 and weighted into grade S/A/B/C/D.
N=.15 U=.20 M=.15 R=.30 V=.20

Feasibility (70%)

Tech Complexity
29.3/40
Data Availability
20.8/25
MVP Timeline
20.0/20
API Bonus
0.0/15
Feasibility Breakdown
Tech Complexity/ 40Difficulty of core implementation stack.
Data Availability/ 25Practical availability and cost of required data.
MVP Timeline/ 20Expected time to ship a usable MVP.
API Bonus/ 15Bonus for viable public API leverage.
Total 100 points; below 50% is filtered out.

Market Validation (60/100)

Competition
8.0/20
Market Demand
6.2/20
Timing
16.0/20
Revenue Signals
10.5/15
Pick-Axe Fit
12.0/15
Solo Buildability
7.0/10
Validation Breakdown
Competition/ 20Signal quality from competitor landscape.
Market Demand/ 20Demand proxies from search and mention patterns.
Timing/ 20Fit with current shifts in tech, behavior, and regulation.
Revenue Signals/ 15Reference evidence for monetization viability.
Pick-Axe Fit/ 15How well the concept serves participants in a trend.
Solo Buildability/ 10Practicality for lean-team implementation.
Total 100 points; below 50 is filtered out.

Technical Requirements

Backend [medium] Frontend [medium] Data Pipeline [low]
Dashboard