Backtest fallback and late listings

Some markets only have prices from a later date; the Backtest fallback decides where their share of the portfolio waits until then.

If you've opened a default portfolio and found a box at the bottom of the Weights panel saying Backtest fallback: Exponential Order Flow Pressure - SOXX, with a dense paragraph under it, this page is for you. The short version: it only matters for the early years of the backtest, and it doesn't affect anything you'd do today.

The problem it solves

Portfolios replay their history from 1 January 2015. Several markets on the boards didn't exist then. ETH's prices start in August 2015, SOL's in April 2020, HYPE's in December 2024 and VVV's in January 2025. These are late listings.

Say a board gives HYPE 20% of the account. Before December 2024 nothing can buy HYPE. If that 20% simply went to the other strategies, the early years would show a different portfolio from the one you built. So the board keeps HYPE's share set aside, and the Backtest fallback decides what that share does while it waits.

The panel's own text says the same thing in fewer words: "Some markets have no bars yet in this window. This row holds that slice until they start, then hands it to those strategies. Open trades are not sold."

The choices

The menu offers three kinds of fallback:

• Cash: the waiting share is lent to strategies of the same class that already have prices (HYPE's share goes to the BTC strategies, for instance) and taken back when the late strategy enters. If no strategy in that class has prices yet, it sits in cash.
• Buy & Hold of a market, like BTCUSD B&H: the share is invested in that market and rises and falls with it.
• A strategy on the board, like Goldenbaum T3 - BTCUSD: the share follows that strategy, invested while it's Long and in cash while it's Flat.

[1. The Backtest fallback menu on a board you own, with the explanation under it.]

Some options carry a date, such as "HYPE B&H (from 2024-12)". That's the "Choices marked 'from'" in the panel's text: those choices only start later themselves, so they hold cash until their own prices begin. Pick something that has prices from your window's start.

On a default the fallback is shown as plain text. Duplicate the board to change it. If you narrow the window so that your saved choice has no prices, the board tells you ("Saved fallback (…) is not available in this window…") and keeps your setting for when the window allows it again.

When the market starts

On the first day the late market has prices, the waiting share leaves the fallback and turns into cash, including whatever it gained or lost while it waited. If the late strategy is Long that day, it buys right away; if it's Flat, it waits for its next Long signal like any other strategy. Nothing already open is sold to make room.

In a dynamic mix, a rule's budget for a class goes to whichever strategies of that class already have prices. Only a destination with no priced strategy at all, like a rule that allocates to HYPE before December 2024, is held back for the fallback.

A real example

Altcoin Dominance [GPS] is mostly ETH, SOL, HYPE and VVV, and uses Goldenbaum T3 - BTCUSD as its fallback. In 2015 most of its allocation had nowhere to go yet:

Does it matter if I start today?

Not really. Every market on the boards has prices now, so nothing is waiting in a fallback at the end of the window, and the Current chart shows no fallback slice. The setting shapes the early years of the equity line and the long-run figures like CAGR, which is worth knowing when you read them: the early years of a board with HYPE or VVV were partly run on something else.

The defaults' choices

Related

• How the simulated account moves
• Markets and asset classes
• Dynamic mix: rules
• Why does my portfolio...