Marketable security?

The definition means 'no real asset is exchanged'.  What is exchanged is a legal contract by a counter party to provide goods or currency in the future. The emphasis is on personal contract, a pre-qualified agent promising to deliver makes liquidity.

The stock market buys and sells personal contracts, all buyers and sellers know the stock represents a uniform balance sheet structure with stability guaranteed by the personal employment contracts of the employees. The stock market has liquidity because it has a wlll layer software format actually, the standard corporate spreadsheet. 

All of these 'liquidity standards' are subject to becoming computerized, layered contracts, monitored by our select trusted miners. Being based on standard personal contracts, we have a provable finite graph transaction, the corporate spreadsheet is, yet again, a step or skip directed graph and all exit states can be measuring by queuing in real time. 

All of this subject to simple automaton with networks of linux processors.   And it is happening, except fr one thing.  The small player has a right to prove his reliability, in proportion to her cash flow.  We need a device to take with us, a device that can prove our compliance with  low transaction costs. It is not fair to leave the technology only to the wealthy, techies have a market and moral issue here, they need to promote autonomous, private key holding provable bots, handheld contract managers.

The topic is arising in central banking again, what should the central banker buy and sell?  It really wants to measure the willingness of dollar holders to obey the contract, live with budget balance, their baskets optimally full.  That is the measure of future investment uncertainty, the bounds on currency risk.  Any currency issuer really need the individual agents to hold savings to loan balances, which it can observe by allowing individuals to hold accounts if they meet reserve rules.  So the Fed always has the best measure of our willingness to make promises about the future at a uniform risk level in measurement.  This keeps currency risk bounded, it is, in effect, the current consensus and a shared cost.