Today, "health care is an open market, but it's not an efficient market," Cuban told John. "When someone gets a prescription, the doctor says, 'OK, you need to take this medication,' and the next words out of the doctor's mouth are, 'What pharmacy do you use?' There's absolutely no discussion of economics at all."

When employers use traditional pharmacy benefit managers, they often have a hard time getting basic information about claims, the rebates the PBMs have negotiated and where the rebate value is flowing, Cuban added.

Cuban argued that the prescription drug market and other health care markets can work like the market for fruits and vegetables if the suppliers provide enough information.

"If you want an efficient market, you have to have pricing available for everybody to evaluate," Cuban said.

When a patient is using a drug discount card at a store, "we want to make it easy for people to be able to do the things that they normally do, that are low-cost transactions like buying lettuce," Cuban said. "I should just be able to go and have the software figure out the lowest prices for us."

The backdrop: Cuban started out as a personal computer software pioneer. He later was one of the owners of the Dallas Mavericks basketball team and a regular on the ABC reality TV show "Shark Tank."

In 2022, he launched Cost Plus Drug in response to complaints that big PBMs like Cigna's Express Scripts, CVS Health's Caremark and UnitedHealth's OptumRx were using opaque negotiating strategies and benefits structures that increased out-of-pocket costs for the patients and kept much of the value of any discounts they negotiated with drug manufacturers.

Related: Employers need to stop maximizing PBM drug plan rebates, says Mark Cuban

Cuban's mail-order pharmacy prices drugs by adding 15% to the wholesale price, then charging a $5 per-prescription pharmacy fee and a $5-per-prescription shipping fee.

Cuban's views: The transparency the Cost Plus Drug mail-order pharmacy and discount card program provide make the prescription drug market more efficient, Cuban said.

"The greatest impact we've had is publishing our price list," Cuban said. "Up until we published our price list, nobody really had one place to go to see what a particular drug cost or sold for."

Simply publishing the price gives health plan sponsors, consultants and brokers information they can use to push for lower prices, Cuban said.