In some cases, Makara may not be able to fully deploy your USD funds into your baskets and the underlying digital assets due to trade limits. For example, if your portfolio has a relatively low account balance but you are widely diversified across a high asset count you might see a small percentage of your funds sitting in USD even though you are not subscribed to the Dollar Basket.
When Makara trades your funds we do so on Gemini Exchange, which has an order minimum of ~$.50 per asset. Approximately $.50 for each asset in your portfolio will not be tradable and will be held as USD.
We are working with Gemini to improve trade efficiency and hope to reduce these USD remainders in the near future. For now the best way to reduce the percentage of your portfolio sitting in USD is to increase the overall size of your portfolio with additional deposits, or reduce your basket subscriptions.