Reality Modeling

public override void Initialize()
{
    var security = AddEquity("SPY");
    // Use 3x leverage on the selected security, which mimic the actual buying power of your broker
    security.SetBuyingPowerModel(new SecurityMarginModel(3m));
}

def initialize(self) -> None:
    security = self.add_equity("SPY")
    # Use 3x leverage on the selected security, which mimic the actual buying power of your broker
    security.set_buying_power_model(SecurityMarginModel(3))

public class BrokerageModelExampleAlgorithm : QCAlgorithm
{
    public override void Initialize()
    {
        // In the Initialize method, set the security initializer to seed initial the prices and models of assets.
        SetSecurityInitializer(new MySecurityInitializer(BrokerageModel, new FuncSecuritySeeder(GetLastKnownPrices)));
    }
}

public class MySecurityInitializer : BrokerageModelSecurityInitializer
{
    public MySecurityInitializer(IBrokerageModel brokerageModel, ISecuritySeeder securitySeeder)
        : base(brokerageModel, securitySeeder) {}    
    public override void Initialize(Security security)
    {
        // First, call the superclass definition.
        // This method sets the reality models of each security using the default reality models of the brokerage model.
        base.Initialize(security);

        // Next, overwrite some of the reality models
        security.SetBuyingPowerModel(new SecurityMarginModel(3m));    }
}

class BrokerageModelExampleAlgorithm(QCAlgorithm):
    def initialize(self) -> None:
        # In the Initialize method, set the security initializer to seed initial the prices and models of assets.
        self.set_security_initializer(MySecurityInitializer(self.brokerage_model, FuncSecuritySeeder(self.get_last_known_prices)))

# Outside of the algorithm class
class MySecurityInitializer(BrokerageModelSecurityInitializer):

    def __init__(self, brokerage_model: IBrokerageModel, security_seeder: ISecuritySeeder) -> None:
        super().__init__(brokerage_model, security_seeder)    
    def initialize(self, security: Security) -> None:
        # First, call the superclass definition.
        # This method sets the reality models of each security using the default reality models of the brokerage model.
        super().initialize(security)

        # Next, overwrite some of the reality models
        security.set_buying_power_model(SecurityMarginModel(3))

public class CustomBuyingPowerModelExampleAlgorithm : QCAlgorithm
{
    public override void Initialize()
    {
        var security = AddEquity("SPY");
        // Set the custom buying power model of the selected security to mimic its actual buying power in your used broker
        security.SetBuyingPowerModel(new MyBuyingPowerModel());
    }
}

// Define the custom buying power model
class MyBuyingPowerModel : BuyingPowerModel
{
    public MyBuyingPowerModel(
        decimal leverage = 2m,
        decimal requiredFreeBuyingPowerPercent = 0m)
        : base(leverage, requiredFreeBuyingPowerPercent)
    {
    }

    public override decimal GetLeverage(Security security)
    {
       return base.GetLeverage(security);
    }

    public override void SetLeverage(Security security, decimal leverage)
    {
        base.SetLeverage(security, leverage);
    }

    public override InitialMargin GetInitialMarginRequiredForOrder(
        InitialMarginRequiredForOrderParameters parameters)
    {
        return base.GetInitialMarginRequiredForOrder(parameters);
    }

    public override MaintenanceMargin GetMaintenanceMargin(
        MaintenanceMarginParameters parameters)
    {
        return base.GetMaintenanceMargin(parameters);
    }

    protected override decimal GetMarginRemaining(
        SecurityPortfolioManager portfolio,
        Security security,
        OrderDirection direction)
    {
        return base.GetMarginRemaining(portfolio, security, direction);
    }

    public override InitialMargin GetInitialMarginRequirement(
        InitialMarginParameters parameters)
    {
        return base.GetInitialMarginRequirement(parameters);
    }

    public override HasSufficientBuyingPowerForOrderResult HasSufficientBuyingPowerForOrder(HasSufficientBuyingPowerForOrderParameters parameters)
    {
        return base.HasSufficientBuyingPowerForOrder(parameters);
    }

    public override GetMaximumOrderQuantityResult GetMaximumOrderQuantityForDeltaBuyingPower(GetMaximumOrderQuantityForDeltaBuyingPowerParameters parameters)
    {
        return base.GetMaximumOrderQuantityForDeltaBuyingPower(parameters);
    }

    public override GetMaximumOrderQuantityResult GetMaximumOrderQuantityForTargetBuyingPower(GetMaximumOrderQuantityForTargetBuyingPowerParameters parameters)
    {
        return base.GetMaximumOrderQuantityForTargetBuyingPower(parameters);
    }

    public override ReservedBuyingPowerForPosition GetReservedBuyingPowerForPosition(
        ReservedBuyingPowerForPositionParameters parameters)
    {
        return base.GetReservedBuyingPowerForPosition(parameters);
    }

    public override BuyingPower GetBuyingPower(BuyingPowerParameters parameters)
    {
        return base.GetBuyingPower(parameters);
    }
}