equity.md

Equity

Equity represents a listed share, ETF, or similar cash-market security. Nautilus uses this type for instruments that trade in whole units, quote in one currency, and have no contract expiry.

Examples include AAPL.XNAS, MSFT.XNAS, and venue-specific ETF symbols.

Fields

Field	Rust type	Python type	Required/default	Notes
instrument_id	InstrumentId	InstrumentId	Required	Stored as id in Rust.
raw_symbol	Symbol	Symbol	Required	Native venue symbol.
currency	Currency	Currency	Required	Quote and settlement currency.
price_precision	u8	int	Required	Decimal places allowed for prices.
price_increment	Price	Price	Required	Smallest valid price step.
lot_size	Option<Quantity>	Quantity	Required/Python	Board lot or whole‑share lot size.
ts_event	UnixNanos	int	Required	Event timestamp in nanoseconds.
ts_init	UnixNanos	int	Required	Initialization timestamp in nanoseconds.
isin	Option<Ustr>	str | None	None	International Securities ID when known.
max_quantity	Option<Quantity>	Quantity | None	None	Maximum order quantity.
min_quantity	Option<Quantity>	Quantity | None	None	Minimum order quantity.
max_price	Option<Price>	N/A	Rust only	Maximum valid quote or order price.
min_price	Option<Price>	N/A	Rust only	Minimum valid quote or order price.
margin_init	Option<Decimal>	Decimal | None	0	Initial margin rate.
margin_maint	Option<Decimal>	Decimal | None	0	Maintenance margin rate.
maker_fee	Option<Decimal>	Decimal | None	0	Maker fee rate. Negative values rebate.
taker_fee	Option<Decimal>	Decimal | None	0	Taker fee rate. Negative values rebate.
tick_scheme_name	N/A	str | None	None	Registered variable tick scheme name.
info	Option<Params>	dict | None	None	Adapter metadata.

Note: Python constructors use instrument_id; Rust stores the same value as id.

Behavior

• Equity has asset class Equity and instrument class Spot.
• Quantity precision is always zero, so orders use whole-share quantities.
• The multiplier and size increment are one.
• It has no base currency, expiry, strike, option kind, or inverse costing flag.
• Use price limits only when the venue publishes them.

Example

<Tabs items={['Rust', 'Python']}>

use nautilus_model::instruments::Equity;

fn listing_summary(instrument: &Equity) -> String {
    format!("{} trades in {}", instrument.raw_symbol, instrument.currency)
}

from nautilus_trader.model.instruments import Equity


def listing_summary(instrument: Equity) -> str:
    return f"{instrument.raw_symbol} trades in {instrument.currency}"

Adapters

Representative adapters that create or consume Equity instruments include:

• Databento for listed US equities and ETFs.
• Interactive Brokers for listed equity contracts.

Related guides

• Data explains market data that references instruments.
• Value types explains Price, Quantity, and Money.