Nobody sells a strategy that failed its backtest.

Every strategy for sale has a beautiful curve. What it does not have is a check run by someone with no reason to make it look good. Now it can.

1998+Delisted-inclusive daily price history in our own dataset
Point-in-timeIndex membership & fundamentals as knowable on the day
Rebuilt twiceA second, independent implementation rebuilds the strategy from the written thesis alone, and the two must agree before any figure counts
$999Launch price, per strategy: $499 to start, $500 when the report is ready. Full refund if we can't run the test

Most backtests fail for boring reasons

Not fraud. Plumbing. A backtest run on today's index members never sees the companies that were removed. One run on restated fundamentals knows things nobody knew at the time. One that fills at the same bar's close trades on information that didn't exist yet. Each leak is worth points of CAGR, and none of them show up in the equity curve.

Survivorship

Testing on the current S&P 500 or Nasdaq-100 silently drops every delisted, acquired, and failed name, usually the worst performers. Our membership is reconstructed as of each historical date.

Lookahead

Fundamentals enter our tests when they were actually public, shares outstanding are the historical figures, and execution is at the next open, never the same bar that produced the signal.

One lucky window

A strategy tuned on a single start and end date may be an artifact of both. We roll the window, split out the fresh era, remove the biggest winners one at a time, and delay the trades to see what survives.

How it works

You send us your strategy in one form and pay $499 to start. We rebuild it and test it, and email you a private link to the finished report. You never need an account.

01

Send the thesis

Tell us the rules, the universe, the window, and the results you claim. You pay $499 to start, not the full price up front.

02

We check it can run

We read your strategy and confirm the test can be run fairly on it. If it is too incomplete to test, we refund you in full and tell you what is missing.

03

We rebuild it twice

A second, independent implementation rebuilds your strategy from the written thesis alone, on data as it was known at the time. No figure counts until the two implementations agree, and the unmodified strategy reproduces first.

04

You get the report

Status updates by email as it moves. The finished report arrives through a private link and unlocks in full once the final $500 is paid. Forward it to anyone. Make it public only if you choose to.

A replication is not a backtest.

A backtest grades its own homework

You run your code on data you assembled and read the number it gives you. Its failure modes are invisible from inside: the data usually holds only companies that still exist, fundamentals as they were later restated, index membership as it stands today projected backward, and your own code deciding what counts as a fill.

A replication is a rebuild by someone else

  • A second implementation is written from your written thesis alone, blind to your code and your numbers. Your stated result has to reproduce first, and the two implementations must agree before any figure counts.
  • The tests are built to kill, not to confirm: walk-forward, a fresh-era split, leaving one stock out at a time, placebos, parameter plateau, delay and cost stress.
  • The verdict comes from a party with no stake in the answer. It can be "does not replicate." It has been, on our own strategies.

The data is the market as it was known on the day

Point-in-time membership

S&P 500 and Nasdaq-100 membership as of each historical date, built from index announcements and filings.

Delisted names included

Companies that later failed or were delisted are still in, with their final returns.

Historical shares outstanding

So a company's size in the test is its size then, not its size now.

Fundamentals as filed

Stamped with when they were actually filed, so a number exists in the test only after it existed in the world.

That is why the same strategy can show a spectacular result in a backtest and fall apart in a replication. The rules did not change. The data stopped helping it.

What we can model

A strategy is more than a signal. How money moves in and out, what the portfolio holds, and what taxes and costs take along the way all change the result. These are modeling choices you set in your thesis, and they are included with every report.

Money in and out

A lump sum, or scheduled contributions: weekly, monthly, quarterly, or annual dollar-cost averaging. Withdrawals as a fixed amount or a percentage of the portfolio, plus one-time deposits or withdrawals in the middle of the test. When money moves, we report the money-weighted return alongside the time-weighted return, because the two can tell different stories.

Assets

Individual stocks and ETFs. Bonds and bond funds. A cash or T-bill sleeve. Commodities, gold, and REITs. Several asset classes in one portfolio, tested together. Leveraged and inverse ETFs, with their daily reset handled honestly.

Taxes and costs

After-tax results, with short-term and long-term gains shown separately, and taxable versus tax-advantaged account framing. Dividend reinvestment on or off. Commissions, slippage, and execution delay. Ongoing fund fees shown as their own drag line, and inflation-adjusted (real) returns next to nominal ones.

Portfolio rules

Rebalancing on a calendar schedule, or only when weights drift past a tolerance band. Glide paths, where the weights change over time. Volatility targeting, where exposure scales with measured risk.

Where it matters, reports also show benchmark-relative statistics. Included in every report is the run with the settings in your thesis: your contribution schedule, your account type with after-tax results and the short-term and long-term gain split, dividend handling, rebalancing rules, and a glide path if your rules specify one. The studies that go further, full tax modeling across both account types, a glide path compared against fixed weights, and withdrawal sustainability, are separate checks priced on request.

Every report runs the same battery

Every report runs the same set of checks, the same way. A free public report gets exactly the same treatment as a paid private one.

Control-reproduction gate Fixed-anchor walk-forward Rolling 4-year CAGR distribution Fresh-era (2022+) split Leave-one-ticker-out Placebo tests Parameter-plateau check DSR / PBO overfitting statistics Delay & cost stress
REPLICATED

The independent rebuild matches the claim within tolerance and holds up across the battery, windows, eras, delays, and costs.

REPLICATED WITH CAVEATS

The headline number reproduces, but something narrows it: one era carries it, one ticker carries it, or it sits on a parameter cliff.

DOES NOT REPLICATE

The claim does not survive point-in-time data, honest execution, or the out-of-sample splits. The report names what explains the gap.

Free published reports you can read first

Traders post strategy claims in public every day: a CAGR, a Sharpe ratio, an equity curve. We take some of the complete, specific ones, replicate them, and publish the full report, whether the claim holds up or not. Anyone can read them, and they show you exactly what a paid report looks like before you buy one.

That openness applies only to strategies that are already public. A report you commission is different: it is 100% confidential, and the strategy and the report are your intellectual property. We never publish it, share it, or reuse it for anyone else. It becomes public only if you decide to make it public.

One strategy. One rebuild. One verdict.

$999 launch price per strategy: $499 to start, $500 when the report is ready, and the start payment refunded in full if we can't run the test. Read a free published report first if you want to see the work before you pay.

Priced per strategy. Not per hour, not per variant.

One set of rules, one universe, and one window make one report. If you change the rules, the parameters, or the universe, that is a different strategy and a separate report.

Launch price · First 10 reports

Replication Report

$999 launch price, per strategy

$499 to start, $500 when the report is ready. The full report unlocks on the final payment. After the first 10 reports, the standard price is $2,500. Complex cross-sectional equity strategies are quoted before work begins, never after, up to $5,000.

  • Split payment: $499 to start, $500 when the report is ready — nothing like the full price up front
  • Independent rebuild from your written thesis, on our point-in-time dataset
  • Modeling included: lump sum or scheduled contributions (weekly, monthly, quarterly, annual), withdrawals, bonds and other asset classes, after-tax results for taxable and tax-advantaged accounts, and rebalancing rules
  • A second, independent implementation reproduces every figure before any of them is accepted
  • Returns, both ways: time-weighted CAGR, and whenever your thesis has contributions or withdrawals, IRR (money-weighted, XIRR) printed next to it, with total contributed, total withdrawn, and end balance beside it so the figure can be checked
  • Annualized volatility, Sharpe ratio, Sortino ratio, and Calmar ratio
  • Benchmark-relative figures against a named benchmark: alpha, beta, correlation and R-squared, tracking error, and information ratio
  • Drawdowns in full: depth, duration, and recovery time, with a worst-drawdowns table
  • An annual returns table with the best and worst year marked, and annual turnover
  • The full battery: walk-forward, rolling windows, fresh-era split, leave-one-ticker-out, placebos, overfitting statistics, delay & cost stress
  • Verdict: Replicated / Replicated with caveats / Does not replicate
  • Delivered through a private link; make it public only if you choose
  • 100% confidential: your strategy and your report are your IP. We never publish, share, or reuse them
  • Status updates by email; no account to create
  • Start payment refunded in full if we can't run the test
Optional at checkout

Revisions add-on, $99

Up to 3 revisions. A revision is narrowly one of: a corrected reading of an ambiguous part of your spec, an added window or era split, or an added cost or delay assumption, always re-run under the identical battery and verdict standard. A revision can move the verdict down as well as up. Changing the rules, parameters, or universe is a changed strategy and a new checkout.

Who this is for

People whose money rides on a backtest

Strategy sellers, bot builders, and independent traders: anyone whose subscribers, investors, or own money depend on whether a backtest is real. One report covers one strategy, and you can share the result with anyone through the report link.

If you keep trading it, keep checking it

A report describes a strategy up to the day it was written. If you keep trading the strategy, we can check it again on a schedule: new data is added, your live results are compared with the replication, and the verdict is renewed, narrowed, or withdrawn if the strategy stops holding up.

Monthly
$299–499/mo
  • Monthly drift report: live results vs. the replication
  • Verdict renewed, narrowed, or downgraded
  • For strategies you trade or sell actively and want checked every month
Quarterly
~$1,000/qtr
  • Fresh-era roll-forward each quarter
  • Full re-validation at the original standard
  • Verdict renewed, narrowed, or downgraded

Ongoing checks are priced per strategy. Each strategy you want followed needs its own report first.

More checks, priced on request

The standard report runs your strategy with the settings in your thesis: contribution and withdrawal schedules, your account type with after-tax results and the short-term and long-term gain split, dividend handling, rebalancing rules, and a glide path if your rules specify one. The checks below go further than that and are not part of the standard report. If you want one, ask us, in your report or by email, and we will give you a price for the work before we start.

Sensitivity Map

Performance across the neighborhood of your parameters, with the number of variants tried listed in the report. It answers one question: does your result hold across nearby settings, or only at one exact setting? It is not a search for a setting that passes. Contact us for pricing.

Extended history

Run the same strategy over an earlier window than the standard test, where our data reaches back to 1998. Contact us for pricing.

Second universe

The same rules on a different universe or market, to see whether the edge travels or was fitted to one pond. Contact us for pricing.

Full tax modeling

Goes beyond the standard report's after-tax view of your one account: the same strategy modeled in both a taxable and a tax-advantaged account, with dividend treatment and the short-term and long-term gain split compared side by side. Contact us for pricing.

Glide path study

Your glide path tested against the same strategy held at fixed weights, so you can see what the shifting allocation itself adds or costs, rather than taking it on faith. Contact us for pricing.

Withdrawal sustainability

For a strategy meant to fund spending: withdrawal rates tested against the full history, including the bad sequences, with the safe withdrawal rate the strategy can support. Contact us for pricing.

What $999 sits between

OptionPrice levelWhat it actually checks
Freelance backtest audit$25–100Your own data and code, re-run. Inherits every leak in both.
Backtest audit service~$100–500Your rules re-run, or your results reviewed, with robustness tests such as walk-forward.
Robustness software (self-serve)~$1,000–2,900Your strategy on your data, with better statistics. The data is still yours.
Curvilinear$999 launch ($2,500 standard)Your thesis, rebuilt from scratch on independent point-in-time, delisted-inclusive data, by two implementations.
Institutional verificationFrom ~$10,000Operations, valuation, and live returns. The backtest itself is taken on trust.

Send us your strategy

Say how the money moves, too: a lump sum or weekly, monthly, quarterly, or annual contributions; any withdrawals; the account type, taxable or tax-advantaged; and whether dividends are reinvested. If you leave a choice out, we test the plain version and say so in the report.

$499 now, $500 when the report is ready. Start payment refunded in full if we can't run the test.

After the start payment: feasibility check, then email updates as the replication moves. When the report is ready, the final $500 unlocks it in full, delivered through a private link. Commissioned reports are 100% confidential: your strategy and your report are your IP, and we never publish, share, or reuse them.

Questions

Can I see the work before I pay?

Yes. The reports we publish from public strategy posts on X are free to read in full, and the sample report on this site shows the same format, the same checks, and the same standard. Private reports are paid work, so there is no free private report.

What if my spec isn't complete enough?

We tell you, and refund you in full. The money-back promise covers exactly this: if we can't run the test fairly, you don't pay for the attempt.

Who sees my report?

Only you, through a private link. You can forward the link to subscribers or investors, that is what it is for. The report becomes public only if you choose to publish it. The free reports we publish ourselves cover only strategies that were already posted in public; a commissioned report is never one of them.

What counts as a revision?

With the $99 add-on: a corrected reading of an ambiguous spec, an added window, or an added cost/delay assumption, re-run under the same battery and standard, and it can move the verdict either way. Rule, parameter, or universe changes are a new strategy and a new checkout.

Do you tune my strategy until it passes?

No. We test the strategy as you specify it and report what we find. If you want to see how the result changes across nearby parameter values, the Sensitivity Map shows that range and lists every variant tried.

Is my strategy confidential, and who owns the report?

Yes, 100% confidential. A commissioned report is work you paid for: the strategy and the report are your intellectual property, and we claim no rights in either. Your thesis is used only to run your replication. We never publish, share, or reuse your strategy or your report, with anyone, for any purpose. Publishing happens only at your own choice.

Curvilinear
Independent Replication Lab

Buy-the-dip: a published S&P 500 strategy, replicated from its public spec

WINDOW 2000-01-03 → 2024-09-30 UNIVERSE: POINT-IN-TIME S&P 500 DELISTED NAMES INCLUDED ENTRY AND EXIT AT THE CLOSE SPEC: PUBLIC, DISCLOSED IN FULL
VERDICT: REPRODUCED

The strategy was rebuilt from its written spec alone, with no code taken from the source repository, and run on our own point-in-time data. Against the repository's own published replication: 25,617 trades against 25,603 (+0.05%), a win rate of 57.11% against 57.04%, and average win and average loss identical at +3.19% and −2.93%.

First, the published figures have to match

A replication is only worth reading if it lands on the numbers the strategy's own author published. This one does, on both bases the repository publishes, and against the original published anchors behind it.

TRADES (TOTAL-RETURN BASIS)25,617Published 25,603 · +0.05% ✓
WIN RATE57.11%Published 57.04% · +0.07pp ✓
AVG WIN / AVG LOSS+3.19% / −2.93%Identical to published ✓
Metric (total-return basis)Repository's replicationOursDifference
Trades25,60325,617+14 (+0.05%)
Win rate57.04%57.11%+0.07pp
Average win+3.19%+3.19%0.00pp
Average loss−2.93%−2.93%0.00pp
Entries per year (mean)1,0271,024.7−2.3
Entries, quietest year (2008)319318−1, same year
Entries, busiest year (2021)1,5831,5830, same year

Against the original published anchors (about 25,000 trades at 56.81% winners), our run reads 25,617 trades at 57.11%: within +2.5% on a rounded count and +0.30pp on win rate. On the repository's capital-only sensitivity basis, we read 24,672 trades against 24,639 published (+0.13%) and a 56.66% win rate against 56.62%.

The strategy as published

The full spec is public, in the phuazz/buy-the-dip repository. These are the rules exactly as disclosed; the replication implements nothing else.

RuleAs published
UniverseS&P 500 members, point-in-time; membership checked on the signal day
Trend filterClose above the 200-day simple moving average
Dip triggerRSI(5) below 20 (Wilder smoothing)
EntryAt the close of the signal bar
ExitAt the close 5 trading bars later; if the stock is delisted first, at its final print
Position ruleOne open position per stock at a time; trades overlap freely across stocks
CostsNone in the published baseline

What we had to decide

No published spec is complete. The full report logs eight ambiguities and the resolution chosen for each; the four that could move the numbers are these. Nothing was tuned: the stated assumptions were run once per basis, and the only runs are the two bases the repository itself publishes.

AmbiguityResolution
Membership sourceThe repository used Norgate's point-in-time constituents; we used our own index membership spells. This is the main data difference and the expected source of the small residuals.
Indicator warm-upSMA and RSI computed from the first bar in our data (end of 1997), giving about 500 bars of warm-up before the window opens; signals counted only inside the window.
Re-entry on the exit barNot taken: a slot is occupied through its exit close, so the earliest re-entry is the next bar.
RSI seedingStandard Wilder seeding, the variant the repository records as replicating its anchors.

Scope: what this verdict covers

This validates the strategy's published baseline: the per-trade statistics of a costless research rule that enters and exits at the same close it signals on. The mean trade was +0.56% with a profit factor of 1.45, and 15 of the 25,617 exits were delisting exits, which a point-in-time universe handles and a survivorship-biased one cannot.

It says nothing about the repository's Phase 2 weekly live model. That model's rules are not disclosed, so it cannot be replicated, and the repository itself reports that the variant failed its own validation gates. Whether the baseline survives real trading costs and live execution is a separate question, and the baseline does not ask it.

Data & method disclosure

Data. Prices and index membership are point-in-time, from our own records: delisted-inclusive daily prices, with membership as it stood on each signal day.

Method. Window 2000-01-03 to 2024-09-30 for every figure on this page. Implemented from the written spec only; no code was taken from the source repository. Two published bases (total-return and capital-only), each run once, with every ambiguity logged in the full report.

What this report is. A sample report in the same format as the free public reports, based on a completed replication of a publicly published strategy. Private reports are delivered through a private link and stay private unless the customer chooses to publish them. A verdict describes the strategy as specified, on this data, over this window. It is not a promise about live trading.

More checks for this strategy

Want to try different parameters on this strategy? A Sensitivity Map shows performance across the parameter neighborhood and lists how many variants were tried. Extended history and a second universe are also available. Contact us for pricing. If you keep trading this strategy, monthly ($299–499/mo) or quarterly (~$1,000/qtr) re-checks compare new results with this report and renew or change the verdict.

A backtesting tool tests your code. A replication tests your claim.

Backtesting tools are built for developing a strategy: fast runs, your rules, your settings, an answer in seconds. A replication is built for a different moment, when the strategy is finished and the number has to be believed by someone other than its author.

Side by side

The difference is not features. It is who runs the test, on what data, and who the answer has to convince.

Backtesting toolsA Curvilinear replication
The implementationYour code, or rules you type into the tool, or rules its AI writes from your description.A rebuild by us, from your written thesis alone. A second implementation must agree with the first before any figure counts.
The dataThe feed the tool ships with, or one you license and plug in. The standard feeds cover today's surviving companies. Point-in-time membership and delisted names are available, but only through specialist platforms and data add-ons, and wiring them up is your job.Point-in-time index membership with delisted companies still in, historical shares outstanding, and fundamentals as they were filed on the day.
The strategiesRules over price bars. Chart-based tools run one symbol at a time; the portfolio platforms run rotations and allocations, still your own implementation on data you assembled.Portfolios: rotations, allocations across asset classes, contribution and withdrawal schedules, and after-tax results.
The checksStatistics, plus robustness grids that you run and read yourself.A fixed test program, the same for every report: walk-forward, a fresh-era split, leave-one-stock-out, placebo tests, a parameter plateau check, overfitting measures, and delay and cost stress.
The verdictA score the tool gives the run you just did.A verdict from a party with no stake in the answer. It can be "does not replicate", and it has been, on our own strategies.
What you can showScreenshots and exports of your own run.A report on a private link that you can hand to a buyer, a partner, or an investor. The report is your property and stays confidential unless you choose to publish it.
What it costsA subscription or a one-time license, and the work of running it is yours.A fixed price per strategy, paid once, with the report yours to keep.

Three differences that decide the answer

A second implementation

A tool runs the rules you gave it. If what you wrote about the strategy and what your code actually does have drifted apart, the tool cannot know. Our rebuild starts from the written thesis alone, so a gap between the claim and the code is itself one of the findings.

Data as it was known on the day

Unless you have licensed specialist point-in-time data, a tool tests on the market as it looks now: the companies that survived, index membership as it stands today, numbers as they were later restated. We rebuild the market as it was known on each day of the test, with the companies that later failed still in it.

A verdict that can fail

A tool's verdict describes your run. Ours is a judgment about your claim, made by a lab with no reason to protect it. The verdict goes in the report either way, and the same test program has failed strategies of our own, in public.

Which one do you need?

Use a backtesting tool when

The strategy is still being developed and you need fast answers while you change it. Or it trades a single instrument intraday, where the detail of fills inside the bar matters more than portfolio history. Tools are excellent at this, and cheaper than any report.

Use a replication when

The strategy is finished and the number has to travel: to a buyer pricing it, a partner committing capital, an investor doing diligence, or to yourself before real money follows the claim. At that point the question is no longer what your code produces. It is whether anyone else can produce it.

Tools are for building strategies. A replication is for believing them.