MMT is obsessed with the notion of monetary sovereignty. If you are monetary sovereign, that gives you complete financial self-determination. If you want to buy more stuff, you can do it, and no one can stop except to the degree they honor your credit, and specifically at the point of sale. Effectively, you have no credit limit within the scope where your currency serves as the only means of payment, regardless of what "investors" or currency savers, think.
It is important to understand that people care much less about returns on investment or inflation, than the total amount they can save. Generally, people would rather have the ability to work 100 hours to get $1,000, than if they could only work for 10 hours and then they earned a 5% interest rate on that. Returns are not the only consideration, when you can induce people to output more. People tend to forget that "trading" is not the only way to acquire a currency, and this is one reason why monetary sovereignty must be evaluated differently from other forms of credit acceptance. If you have to trade into a spendable medium, that limits the immediacy of financial self determination.
MMTers don't typically discuss this, but having the flexibility to choose to accept different means of payment is the super secret to true financial self-determination... So if you don't want to accept dollars, you don't have to. The only sense in which you are legally obligated to accept dollars, is in civil legal matters, such as tortious debts. If you sue someone for a million dollars, they will always be able to settle that with the sovereign currency.
Well of course, we here at the economics now blog(1 person as of now) want everyone to have the ability to issue their own spendable medium of exchange, but.. that's not easy, so we issue superbonds to allow us the maximum flexibility in the mean time. Effectively, you issue bonds in your own unit of account, a "financial currency", if you will. Then the "exchange rate" for your currency, takes the place of a credit score.
This means, that, as your credit score goes down, you have to pay back less. Investors determine your credit score both by trading to purchase newly issued tokens when you want to raise more capital, and by bidding on your stream of base currency repayments with matured tokens. To allow for some flexibility, you can allow investors to "cash out" to your virtual tokens early, based on how long they waited. If they wait to half the maturity, they only get 50% out. If they wait 90% of the time, they get 90% of the mature amount out. Because they are cashing out to get your virtual tokens, and then using your tokens to bid on the repayment stream in the base currenc(ies), there is no reaon not to allow people to cash out early at a discount.
If you structure it correctly, and everyone waits until full maturity, then the repayment stream should cover all "cash-outs" at 100%. However, if people get skiddish, this allows them to jump ship early, without having to sell their securities to other investors. On the other hand, if you face unexpected contingencies, you can taper down your repayment stream, with the understanding, that people will either have to wait or buy more securities until they can cash out. But the point is, it let's you control the bankruptcy process and repayment schedule, with the understanding that not keeping your word, by extending the schedule or reducing total payments, will hurt your ability to raise capital in the future.
There are two possible ways you can induce investors to buy your "self-tokenized" securities. The standard way is the traditional mechanism of offering a bond with a certain premium or coupon once it matures. So you can sell a $100, 5 year bond for $95, or whatever specific return you want to offer. Then, if you sell $12,000 of bonds extending up to 10 years, you schedule your monthly repayments, which in this case would require $100/month. As people's bonds mature, the pool of "reserves" for repayment is full, so they can cash out of the bonds at full face value.
Let's say that something happens, and then you are forced to lower your monthly payments to $80 for a time. Then, as people's bonds mature, there will be more people holding your virtual currency, than is available in the reserves for repayment. Let's say 85% of investors decide to cashout anyway, and 15% decide to wait until the reserves are there to cashout at full value. So the cashout value is bid down to 80/85 or $94.12 on $100. This amount is called the "cash-out" rate.
The other way you can induce people to buy bonds, is to offer a discount at the "buy-in" rate over the "cash-out" rate. This essentially means you are debasing your currency, so that the new investors get a better conversion rate than the former security purchasers. So if the current cashout rate is 95%, then you can offer a buy-in rate of 90%, such that new security buyers only have to pay 90 cents on the dollar, and can anticipate getting 95 cents on the dollar, when they cash out, in addition the amount that their bonds earn.
Currently, the code for a project to issue these bonds is being developed on github under the name webcmd-py. webcmd-py emulates a command line interface in the browser, so you don't have to write a bunch of different web pages. There will be commands for creating currencies, issuing bonds, converting bonds directly into bitcoins on the server, and tracking payments into other currency conversions.
The parent project was node-web-cmd, with a demo video showing how it works.