MiCA Article 6 stablecoin bundle: whitepaper, iXBRL, cadCAD peg simulation, redemption gate

A MiCA Article 6 stablecoin whitepaper is no longer a PDF — it is a regulated, machine-readable filing. Four artifacts must ship together: the whitepaper itself, an iXBRL filing against the ESMA taxonomy, a peg simulation backing every quantitative claim, and a redemption gate stress test proving the redemption right holds under load. This article walks through how the bundle composes, what math underpins it, and what working code looks like.

Why compliance is engineering, not paperwork

The reflex when a regulator publishes new disclosure rules is to treat the result as a form-filling exercise. For MiCA Article 6 that reflex is wrong, and the deadlines make it expensive.

The CASP transitional period ends on 1 July 2026. Any stablecoin issuer serving EU users — directly or via passporting — needs a MiCA-compliant whitepaper on file. Legacy whitepapers for tokens admitted to trading before 30 December 2024 must be replaced by 31 December 2027, per ESMA Q&A 2654 (17 October 2025). And since 23 December 2025, Commission Implementing Regulation (EU) 2024/2984 requires that the whitepaper itself be filed in Inline XBRL against the ESMA XBRL taxonomy (published 5 August 2025).

Three things the market still gets wrong:

1. Annex I is treated as a checklist of fields rather than a contract whose claims must be testable.
2. Peg-stability assertions are written before any simulation backs them.
3. Redemption gate parameters are copied from legal precedent rather than derived from queue-depth math.

If the whitepaper is a PDF written by counsel, the iXBRL filing becomes a post-hoc translation exercise. If “redemption within 24h under normal conditions” has no simulation behind it, the claim is a liability the moment redemption pressure rises. Compliance is engineering because the supervisor will run automated checks against the iXBRL fields and against on-chain data — the document is queryable.

For a foundational overview of stablecoin mechanics that this article builds on, see stablecoin tokenomics. What follows assumes a fiat-backed EMT (electronic money token) under MiCA Title III, since that is the configuration most issuers preparing for the 1 July 2026 cliff are targeting.

The four-artifact bundle

Article 6 plus Annex I plus the iXBRL ITS plus the redemption-rights rules of Article 49 read as a single engineering brief once the prose is stripped away. There are four artifacts, designed together.

Artifact 1 — the whitepaper. Annex I sets out the disclosure plan: identity of offeror and issuer, characteristics of the crypto-asset, rights and obligations attached to the token, underlying technology, related risks. For EMTs, Annex II adds reserve composition, governance, redemption mechanism, and adverse events disclosure. The prose has to be precise enough that every parametric claim—peg accuracy, redemption time, reserve ratio—maps to a number the iXBRL filing carries.

Artifact 2 — the iXBRL filing. The whitepaper is filed as a single XHTML file with Inline XBRL tagging against the ESMA crypto-asset taxonomy. The supervisor’s tooling parses out structured fields—issuer LEI, token classification (EMT / ART / other), reserve composition, redemption terms, peg mechanism type—and can run automated comparisons against periodic reports and on-chain telemetry. This is what changes the disclosure economics: the filing is queryable.

Artifact 3 — the cadCAD peg simulation. Any quantitative claim about peg behavior in the whitepaper—“peg deviation under normal conditions stays within ±0.1%”, “redemption queue clears within N days under a 5σ stress event”—needs a simulation that produces it. cadCAD is the de facto open-source framework for this; the simulation defines state variables (reserve composition, supply, peg price, queue depth), policies (redemption pressure, reserve mark-to-market), and partial state update blocks (peg deviation, queue dynamics, solvency check).

Artifact 4 — the redemption gate stress test. Article 49 of MiCA gives EMT holders the right to redeem at par at any time. A redemption gate—the Q_max ceiling and the T_max response time the issuer commits to—isn’t a free parameter. It has to be calibrated against the reserve composition’s liquid horizon, the stress scenarios the peg simulation covers, and the operational capacity to fulfill. The whitepaper cites the gate; the simulation justifies it; the iXBRL filing exposes it.

These four ship as a single deliverable because every line of the whitepaper either references the simulation, exposes a field that the iXBRL filing tags, or commits to a stress-tested redemption parameter. Tokenomics.com sells MiCA disclosure documentation as a standalone product; CADLabs publishes open-source cadCAD models; legal firms hand over the whitepaper text. We have not seen a public competitor that bundles all four artifacts behind a single source of truth — which is exactly the gap the supervisor’s automated checks will surface.

Peg and queue dynamics

The peg of a fiat-backed EMT is enforced on the primary market by the redemption right: any holder can present 1 EMT and receive €1 from the issuer. Secondary-market deviations are what the supervisor cares about. They are driven by three forces.

The reserve composition determines the issuer’s capacity to absorb redemption flow without disturbing the market price. A defensible non-significant EMT reserve—roughly 60% short-duration Treasury bills, 35% cash at qualifying custodians, 5% reverse repo—sits comfortably above the EBA RTS minimum 30% bank-deposit share for non-significant EMTs (significant EMTs face a 60% bank-deposit floor and need a correspondingly higher cash share). The liquid horizon is one to three business days for the cash bucket and up to a week for the T-bill bucket after deducting expected mark-to-market.

Redemption pressure on a given day is modeled as a stochastic process. A baseline day sees R₀ ≈ 1–2% of supply requested; a stress day spikes that several multiples higher.

When R(t) > G, the queue grows. When R(t) < G, the queue drains at rate G − R(t). The gate’s role is exactly to convert spike redemption pressure into a fulfillable schedule without forcing the reserve to dump T-bills into a stressed market.

The 1:1 par-value backing for EMTs is set by MiCA Title IV (Articles 48 and 54, with the reserve composition rules of Article 36 applied via cross-reference); Solvency(t) ≥ 0 must hold at all times. In practice the issuer keeps an explicit excess (typically 3–5% of supply) to absorb mark-to-market moves on the T-bill portfolio without breaching the 100% line.

The peg-stability claim in the whitepaper is now an objective function: under the simulated stress events, Δp_max and T_recovery must stay within whatever the issuer commits to. The gate ceiling G and the reserve composition (wᵢ) are the design levers.

Implementation

The implementation section ships two pieces: the cadCAD simulation that backs every peg-stability claim, and the iXBRL Annex I structure that exposes the design to the supervisor. The third piece — an interactive redemption gate stress test — sits in its own section below so it picks up its own TOC anchor, since most readers come here for it.

cadCAD peg simulation

The first deliverable is a parametric peg simulation across three scenarios. Reserve composition is fixed at 60% T-bills, 35% cash at qualifying custodians, 5% reverse repo, with a 5% initial excess over supply — the minimal-bank-deposit configuration that clears the EBA RTS 30% floor for a non-significant EUR-denominated EMT in 2026.

The base scenario is uneventful: gate ceiling sits above ordinary daily flow, the queue never accumulates, and the secondary market reflects effectively no deviation. The stress scenario — 6× normal spike, no reserve repricing — pushes peg deviation under 0.5% with a 4-day clearance. The black-swan combines a 12× spike with a 3% duration shock on the T-bill portfolio (consistent with a 100 bp parallel yield move on a 6-month duration book); peg deviation reaches roughly ±1.1% for two to three days, the solvency margin compresses from +5.0% to +3.2%, and the system recovers within two weeks.

These are the numbers that go into the Annex I disclosure. The whitepaper can credibly state “secondary-market peg deviation stays inside ±0.5% under a 6× redemption spike and within ±1.2% under a 12× spike with a 3% reserve mark-to-market shock, with full redemption fulfillment within 8 days” because the simulation produces those numbers.

# MiCA EMT peg simulation — cadCAD-style configuration
# State: reserve composition, supply, peg price, queue depth, day counter
# Policies: redemption pressure, reserve mark-to-market
# PSUBs: queue update, peg deviation, solvency check

from cadCAD.configuration import Experiment
from cadCAD.configuration.utils import config_sim
import numpy as np

# ---- Initial state ----
# Composition clears EBA RTS Article 36 bank-deposit floor (≥30% for non-significant EMTs).
initial_state = {
    "supply": 1_000_000_000.0,         # outstanding EMT supply (€)
    "reserve_tbills": 0.60 * 1_050_000_000.0,
    "reserve_cash":   0.35 * 1_050_000_000.0,
    "reserve_repo":   0.05 * 1_050_000_000.0,
    "queue_depth": 0.0,                # outstanding redemption queue (€)
    "peg_price": 1.0,                  # secondary-market price
    "day": 0,
}

# ---- Scenario parameters ----
scenarios = {
    "base":       {"spike_pct": 0.02, "gate_pct": 0.05, "normal_pct": 0.02, "mtm_shock": 0.0},
    "stress":     {"spike_pct": 0.12, "gate_pct": 0.05, "normal_pct": 0.02, "mtm_shock": 0.0},
    "black_swan": {"spike_pct": 0.25, "gate_pct": 0.05, "normal_pct": 0.02, "mtm_shock": -0.03},
}

# ---- Policies ----
def p_redemption(params, step, sH, s):
    """Daily redemption pressure: spike on day 1, normal otherwise."""
    if s["day"] == 1:
        R = params["spike_pct"] * s["supply"]
    else:
        R = params["normal_pct"] * s["supply"]
    return {"R": R}

def p_reserve_mtm(params, step, sH, s):
    """One-shot mark-to-market shock on T-bill portfolio at day 1."""
    if s["day"] == 1:
        return {"mtm_loss_tbills": s["reserve_tbills"] * params["mtm_shock"]}
    return {"mtm_loss_tbills": 0.0}

# ---- PSUBs ----
def s_queue(params, step, sH, s, _input):
    """Q(t+1) = max(0, Q(t) + R(t) − G·supply)"""
    R = _input["R"]
    G_amt = params["gate_pct"] * s["supply"]
    q_new = max(0.0, s["queue_depth"] + R - G_amt)
    return ("queue_depth", q_new)

def s_reserve_cash(params, step, sH, s, _input):
    """Liquidity waterfall: drain cash first to fulfill redemptions."""
    G_amt = params["gate_pct"] * s["supply"]
    fulfilled = min(s["queue_depth"] + _input["R"], G_amt)
    drain_cash = min(fulfilled, s["reserve_cash"])
    return ("reserve_cash", s["reserve_cash"] - drain_cash)

def s_reserve_tbills(params, step, sH, s, _input):
    """T-bills absorb whatever cash cannot fund, plus the one-shot MtM loss."""
    G_amt = params["gate_pct"] * s["supply"]
    fulfilled = min(s["queue_depth"] + _input["R"], G_amt)
    drain_cash = min(fulfilled, s["reserve_cash"])
    drain_tbills = fulfilled - drain_cash
    return ("reserve_tbills", s["reserve_tbills"] - drain_tbills - _input["mtm_loss_tbills"])

def s_supply(params, step, sH, s, _input):
    """Supply decreases by fulfilled redemptions."""
    G_amt = params["gate_pct"] * s["supply"]
    fulfilled = min(s["queue_depth"] + _input["R"], G_amt)
    return ("supply", s["supply"] - fulfilled)

def s_peg(params, step, sH, s, _input):
    """Secondary-market peg: delay discount + liquidity premium + solvency concern."""
    queue_pct = s["queue_depth"] / s["supply"] if s["supply"] > 0 else 0
    days_to_clear = queue_pct / max(params["gate_pct"] - params["normal_pct"], 1e-9)
    delay_discount  = days_to_clear * 0.045 / 365
    liquidity_prem  = 0.05 * queue_pct
    reserve_total = s["reserve_tbills"] + s["reserve_cash"] + s["reserve_repo"]
    margin_pct = (reserve_total - s["supply"]) / s["supply"]
    if   margin_pct >= 0.03: solv = 0.0
    elif margin_pct >= 0.01: solv = 0.003
    elif margin_pct >= 0:    solv = 0.01
    else:                    solv = 0.025
    return ("peg_price", 1.0 - (delay_discount + liquidity_prem + solv))

def s_day(params, step, sH, s, _input):
    return ("day", s["day"] + 1)

# ---- Partial State Update Block ----
psubs = [{
    "policies": {"redemption": p_redemption, "mtm": p_reserve_mtm},
    "variables": {
        "queue_depth": s_queue,
        "reserve_cash": s_reserve_cash,
        "reserve_tbills": s_reserve_tbills,
        "supply": s_supply,
        "peg_price": s_peg,
        "day": s_day,
    },
}]

# ---- Run experiment ----
sim_config = config_sim({"T": range(30), "N": 1, "M": scenarios})
exp = Experiment()
exp.append_configs(initial_state=initial_state,
                   partial_state_update_blocks=psubs,
                   sim_configs=sim_config)

The conclusion that goes into the whitepaper and gets tagged in the iXBRL filing is the summary table. The supervisor sees a reproducible parametric claim: under these three scenarios, with these reserve weights and gate parameters, peg deviation and recovery time fall inside these bounds.

iXBRL Annex I structure

The iXBRL filing is the bridge between the prose disclosure and the supervisor’s tooling. Each field below is tagged against the ESMA crypto-asset taxonomy and carried through the XHTML container.

The leverage here is upstream design. If the cadCAD simulation is written first, the Annex II reserve composition fields are populated from the same data structure that drives the simulation. The peg-stability assertions in Annex I.H reference exact Δp_max and T_recovery values from the simulation runs. The redemption mechanism description in Annex I.F cites the gate ceiling G that the stress test certified. The result is a filing where the legal prose and the engineering artifacts share a single source of truth.

When the supervisor’s tooling parses the iXBRL file, it can run automated checks against periodic reserve reports filed under MiCA Article 36 and against on-chain telemetry on redemption fulfillment time. If the whitepaper claims redemption within 5 business days under stress and a public dashboard shows a 9-day fulfillment median, the gap is now an audit finding the issuer has to explain. The flip side is that a well-built bundle survives this scrutiny: the simulation predicted the gap, the filing disclosed it, and the gate parameters reflect the actual reserve liquidity.

Redemption gate stress test

The interactive calculator below reproduces the cadCAD simulation logic. Move the sliders to set redemption pressure, gate ceiling, and reserve shock, and watch peg deviation and recovery time respond. The chart traces queue depth over time after the spike day.

The point of the inline version is reproducibility: a counterparty’s risk team can validate the gate parameters in five minutes without rebuilding the model. A production stress test runs each cell as a Monte Carlo cohort.

Five mistakes we see in MiCA submissions

The bundle described above is not how most issuers approach the filing. Five failure modes recur in submissions our team has reviewed across UAE, Lithuanian, and French entity setups.

Pitfall 1 — Annex I treated as a checklist. The whitepaper text is written by counsel who fills each Annex I field with the minimum compliant prose. There is no underlying engineering brief, so the iXBRL filing becomes a translation exercise: structured fields are populated by reading the prose, not the other way round. The supervisor’s automated checks then surface inconsistencies between the prose, the iXBRL tags, and the periodic reserve reports — because the three were never produced from a single source of truth.

Pitfall 2 — peg-stability claims without simulation. The whitepaper asserts “the peg is maintained through full backing and on-demand redemption”, and Annex I Section H states that peg deviation risk is “low under normal market conditions”. Neither statement is parametric. When redemption pressure spikes — as it did for several MiCA-compliant EMTs in late 2025 — the issuer has no quantitative baseline to compare against, and the disclosure looks marketing-grade rather than engineering-grade.

Pitfall 3 — redemption gate with legal-only parameters. The redemption mechanism section commits to “fulfillment within 5 business days” because that is what counsel suggested as conservative. The gate ceiling is never reconciled with the reserve composition’s liquid horizon. Under a real stress event the issuer either misses the disclosed timeline or dumps T-bills into a stressed market to keep it — both outcomes are worse than disclosing a defensible 8-day fulfillment time backed by the stress test.

Pitfall 4 — iXBRL as a post-hoc conversion. The whitepaper PDF is delivered first; iXBRL tagging is contracted to a third party two weeks before the filing deadline. The tagging team interprets the prose, and gaps surface — Annex II reserve composition fields lack supporting numbers, peg mechanism type does not map cleanly to the taxonomy enumeration, redemption gate parameters appear only in a footnote. The result is either a delayed filing or one that exposes the issuer to interpretation risk for years.

Pitfall 5 — stale reserve composition disclosure. The Annex II reserve disclosure is a snapshot, but the reserve composition shifts continuously as redemptions occur and maturing T-bills are rolled. If the issuer’s periodic reporting under Article 36 diverges from the whitepaper’s stated composition by more than the disclosed tolerance, the supervisor has a documented inconsistency. The fix is to design the disclosure as a band (acceptable composition range) rather than a point, with the stress test confirming peg stability across the entire band.

Compliance-as-design

The iXBRL filing is the structural change. A pre-MiCA whitepaper was a PDF a supervisor read once during approval; a MiCA whitepaper is a machine-readable contract checked continuously against periodic reports and on-chain data. Every parametric claim becomes a tracking metric. The engineering brief has to anticipate this.

The implication for design ordering is sharp. The cadCAD simulation comes first; it produces the numbers. The Annex II reserve composition and the redemption gate parameters come from the simulation. The whitepaper text is written against those numbers. The iXBRL tagging is performed in the same workflow, against the same data structures. The four artifacts share state.

For UAE- and CIS-resident founders planning a MiCA passport, the cross-jurisdiction angle is the lever. A Lithuanian or French entity holds the EMI authorization that triggers MiCA EMT status under Article 48; the operational stack (treasury, custody, governance) can sit closer to home under a VARA framework. The bundle stays the same — only the legal wrapper differs.

The periodic monitoring stream completes the picture. Under MiCA Article 36 the issuer files periodic reserve reports; the supervisor compares them against the iXBRL whitepaper’s stated composition band. A redemption pressure event triggers an obligation to disclose; the issuer’s monitoring stack has to detect it before the supervisor’s tooling does. This is recurring engineering work — telemetry pipes, automated reserve audits, a live cadCAD scenario refresh — not a one-shot filing.

Regulatory sources

Primary regulation: MiCA Regulation (EU) 2023/1114 for Articles 6, 36, 48–49 and Annexes I–II; Commission Implementing Regulation (EU) 2024/2984 for the iXBRL ITS in force since 23 December 2025; the ESMA crypto-asset XBRL taxonomy published 5 August 2025.

ESMA guidance: Q&A 2654 (17 October 2025) on the legacy whitepaper regime and the obligations of trading-platform operators; the Statement on iXBRL/XBRL implementation (28 November 2025); and the Statement on the end of transitional periods (17 April 2026).