Probably by becoming a highly-trusted, low-risk customer. Payment balance float is all about holding some money in reserve in case of chargebacks. The better your stats are, the less money a processor will insist on holding in reserve.
Additionally, I think that a company's level of trust with their customers involves some 'coefficient of risk' regarding potential losses to chargebacks against a low or non-existent reserve. I find the topic interesting, especially the consequences at a federal level if you guess wrong and the "customer" turns out to be laundering money.