Lontevis

Documentation

Understand how Lontevis models retirement withdrawals, or integrate our optimization engine into your advisory platform via the REST API.

Quickstart

Enter your retirement profile to get optimized withdrawal strategy in under 5 minutes.

Monte Carlo Simulation

10,000+ portfolio longevity trials sampling from historical equity and bond return distributions.

SS Break-Even Analysis

Mortality-weighted NPV of claiming at ages 62-70, with spousal and survivor benefit coordination.

Tax-Aware Sequencing

Dynamic programming for optimal draw order across taxable, Traditional, and Roth accounts.

Roth Conversion Optimizer

Identify annual conversion amounts that fill lower brackets without triggering IRMAA surcharges.

RMD Integration

IRS Uniform Lifetime Table applied to tax-deferred accounts per SECURE 2.0 age thresholds.

API Endpoints

POST/v1/optimize
POST/v1/monte-carlo
GET/v1/ss-breakeven
GET/v1/tax-brackets/:year
GET/v1/rmd-table
POST/v1/signup
POST/v1/checkout

Authentication

All API requests require an API key via the X-API-Key header.

curl https://api.lontevis.smarttechinvest.com/v1/ss-breakeven \
  -H "X-API-Key: lon_your_api_key_here"

Monte Carlo Portfolio Simulation

We run 10,000+ trials sampling from historical return distributions for equities (S&P 500 total return, 1926-present), bonds (10-year Treasury constant maturity), and TIPS. Each trial models annual withdrawals against a declining portfolio, incorporating RMDs, Social Security income, and pension payments.

The simulation produces:

  • Ruin probability -- percentage of trials where the portfolio is exhausted before death
  • Safe withdrawal rate -- maximum inflation-adjusted withdrawal rate with less than 5% ruin probability
  • Median portfolio at death -- expected bequest amount
  • Fan chart -- 10th/25th/50th/75th/90th percentile portfolio paths over time

Social Security Break-Even Analysis

For each claiming age (62-70), we compute the mortality-weighted net present value of lifetime benefits using SSA period life tables (Table 4c6). The analysis incorporates early claiming reduction (6.67%/year before FRA), delayed retirement credits (8%/year after FRA), and spousal/survivor benefit coordination.

The optimal claiming age depends on your life expectancy, discount rate, tax situation, and portfolio size. Delaying to 70 is optimal for many retirees with sufficient portfolio assets to bridge the gap.