Putting Aschenbrenner’s book inside Your ISA,
without options.

A 13F lists every position as a separate row — long stock, long call, long put — even when they’re on the same name. The first step is to net them, with a delta haircut. Common stock counts at 1.0 delta. Options on the 13F are reported at underlying notional, but a real at-the-money put or call has ~0.5 delta — meaning $1 of underlying notional translates into about $0.50 of actual dollar-of-direction exposure.

So for Micron: long $5.9M of stock + (0.5 × $422.3M calls) − (0.5 × $583.7M puts) = 5.9 + 211 − 292 = −$75M of net short dollar-delta. That’s the number the ISA targets.

Each net-long name becomes a direct purchase of the underlying US share. Most UK ISA providers (Hargreaves Lansdown, Interactive Investor, AJ Bell, Trading 212, Interactive Brokers UK) accept US equities into an ISA once a W-8BEN is on file.

Each net-short name becomes a position in an LSE-listed −3x daily-reset inverse ETP. To get $X of short delta you only need $X/3 of capital, because the ETP delivers 3× the inverse of its underlying. So if the delta-adjusted bet on NVIDIA is −$784M, the ISA emulator holds $784M / 3 ≈ $261M of 3SNV (GraniteShares 3x Short NVIDIA).

Five things this construction quietly assumes:

1. Average option delta is ~0.5. Without strikes, that’s an ATM-mix proxy. Deep-ITM puts behave more like outright shorts (delta ~1); deep-OTM puts barely move (delta ~0.1). If you think the fund is buying cheap OTM tail-risk hedges, scale the inverse sleeve down; if you think it’s ITM-heavy, scale it up.
2. Path-dependency of −3x daily-reset products is acceptable. Over multi-week holding periods in volatile markets, the product will drift below the implied 3× short return — sometimes meaningfully.
3. Single-stock inverse ETPs exist for most of the put names. They do for NVDA, ASML, TSMC, Intel; they’re less certain for Broadcom, Micron, Oracle — flagged inline.
4. You will rebalance. Daily-reset inverse ETPs need to be re-weighted on a regular cadence; let weights drift and the construction quietly degrades.
5. Some 13F lines can’t be replicated cleanly. The 3x-short AMD product (3SMD) was terminated by GraniteShares in October 2025 after an intraday surge wiped out the index; AMD short exposure has to be picked up via a sector inverse or skipped.