How the model works

Short notes on LadderUp’s income-first retirement model: the Security Ratio, TIPS bond ladders, Social Security claiming, and how to read the simulation results.

These notes explain the LadderUp retirement-planning framework in plain language. They are the best place to learn what the research prototype is doing before you read the working paper or run the model.

• Why this planner exists

  LadderUp treats retirement as an income problem, not a portfolio-size problem. Learn why wealth targets and the 4% rule leave future spending exposed to markets.

• Stocks and bonds in this model

  How LadderUp uses stocks to build future income and TIPS held to maturity to lock it in—unlike target-date funds and bond ETFs that still carry interest-rate risk.

• How Much of Your Retirement Income Should Be Secured?

  The Security Ratio measures how much of your desired retirement income is already guaranteed. See how SR, SR0, and income smoothing shape retirement readiness.

• When can you retire?

  LadderUp says you can retire when income capacity covers your goal and the Security Ratio hits your target—not when a portfolio number is reached.

• When Should You Claim Social Security?

  How LadderUp estimates Social Security benefits and lets claiming age emerge from the simulation when those benefits improve retirement readiness.

• Reading your results

  How to read LadderUp plan summaries, glide paths, income charts, and percentile tables after you run the Monte Carlo allocation solver.