Allow Live Books to Match Simulated Gross Exposure (e.g. 130/30, 90/50)

Feature Requests
1

After learning this is a known issue, I wanted to submit a focused feature request because I think this materially impacts research-to-production consistency on P123.

Current Behavior

Simulated books appear to support gross exposure >1.0 (for example 90/50 or 130/30 long/short structures), but live books seem constrained to gross exposure ≤1.0.

This creates a disconnect where strategies that are valid in simulation cannot be deployed equivalently in production.

Why This Matters

For many market-neutral and factor-based strategies, gross exposure is a core portfolio construction parameter — not simply “extra leverage.”

Examples:

  • 130/30 enhanced equity

  • 90/50 market-neutral tilts

  • Beta-neutral factor portfolios

  • Long/short statistical arbitrage

If live books net long and short capital differently than sims, performance characteristics can diverge significantly:

  • factor exposure

  • volatility

  • turnover

  • hedging effectiveness

  • drawdowns

  • realized alpha

Proposed Solution

Ideally, live books would support configurable gross exposure limits consistent with sims, subject to broker margin constraints.

Even a simple implementation would solve most of the issue:

  • Add a “Max Gross Exposure” parameter to live books

  • Default = 1.0 for backward compatibility

  • Allow values >1.0 when supported by broker/account permissions

Minimal Initial Version

Even read-only validation would help initially:

  • warn users if sim gross exposure exceeds live-supported exposure

  • show expected live gross exposure behavior before deployment

That alone would reduce accidental sim/live mismatch.

Why This Is High Leverage for P123

This would meaningfully improve:

  • institutional usability

  • long/short workflow credibility

  • sim-to-live fidelity

  • advanced factor strategy deployment

It also closes one of the bigger gaps between research infrastructure and actual execution.

Curious whether this is already on the roadmap and whether the limitation is primarily:

  1. broker API related,

  2. margin accounting related, or

  3. internal live-book architecture related.