Key Concepts


The Portfolio object provides information about the whole portfolio state.


The Portfolio object has the following properties:

var invested = Portfolio.Invested;
var value = Portfolio.TotalPortfolioValue;
invested = self.Portfolio.Invested
value = self.Portfolio.TotalPortfolioValue

Cost Averaging Accounting

LEAN uses the cost averaging accounting method, which determines the cost of your holdings by taking a weighted average of all your purchase prices. For example, say you place the following buy orders:

  1. Buy 10 ABC @ $10
  2. Buy 5 ABC @ $11
  3. Buy 20 ABC @ $14
  4. Buy 3 ABC @ $9

In the preceding example, the average cost of your ABC position is (10*10 + 5*11 + 20*14 + 3*9) / (10 + 5 + 20 + 3) = $12.1579/share. In contrast, if you use the first-in, first-out (FIFO) accounting method, the cost of the first 10 shares is $10/share, not $12.1579/share.

Long and Short Holdings

You can identify a position as long- or short-biased based on the sign of the holding quantity. Long positions have a positive quantity and short positions have a negative quantity.

Buying Power

To get the maximum order size you can place for a given Symbol and order direction, call the GetBuyingPower method.

var quantity = Portfolio.GetBuyingPower(_symbol, OrderDirection.Buy);
quantity = self.Portfolio.GetBuyingPower(self.symbol, OrderDirection.Buy)

For more information about buying power, see Buying Power.

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