Custom PCM Insufficient buying power

The error message you're seeing is related to buying power. It means that the algorithm doesn't have enough cash to execute the orders. The ImmediateExecutionModel places trades as soon as it receives the targets from the Portfolio Construction Model, but it doesn't check if there's enough buying power to execute these trades.

The weights you're calculating in your Portfolio Construction Model are used to determine the proportion of the portfolio's value that should be invested in each security. However, if the sum of these weights exceeds the available buying power, you'll get an "Insufficient buying power" error.

One thing you could try is to add a check in your Portfolio Construction Model to ensure that the sum of the weights doesn't exceed the portfolio's buying power. You can get the portfolio's buying power using the algorithm.Portfolio.GetBuyingPower(symbol, OrderDirection.Buy) method.

Here's an example of how you might modify your code:

total_weight = sum(self.symbol_weights.values())
buying_power = sum(algorithm.Portfolio.GetBuyingPower(symbol, OrderDirection.Buy) for symbol in self.symbol_weights.keys())

if total_weight > buying_power:
    # Scale down the weights so they don't exceed the buying power
    scale_factor = buying_power / total_weight
    self.symbol_weights = {symbol: weight * scale_factor for symbol, weight in self.symbol_weights.items()}

targets = []
for symbol, weight in self.symbol_weights.items():
    targets.append(PortfolioTarget.Percent(algorithm, symbol, weight * 0.98 / sum(self.symbol_weights.values())))

This code scales down the weights if their sum exceeds the portfolio's buying power, which should prevent the "Insufficient buying power" error.

Please note that this is just a suggestion and you might need to adjust the code to fit your specific needs.

Sources:

• Forum Discussion: Issues with order fills and execution
• Docs: Buying Power
• Docs: Execution Key Concepts
• Forum Discussion: ImmediateExecutionModel not executing immediately