A decentralized securities trading and settlement system is being built hidden in plain sight

Colored coins, chromawallet, coinprism, NXT Asset Exchange, Mastercoin, Counterparty… tens of projects are working on asset tracking, transfer and exchange systems. What are they doing? Will it work?

I wrote a piece last year explaining how today’s securities trading and settlement systems work. The full picture of participants is pretty complex:

Figure 8 csd

There are surprisingly many parties involved in the safekeeping and exchange of securities. What would the picture look like in a “decentralized world”?

At core, I think the system is all about assuring “performance”. That is… it’s all about making sure that people actually deliver on the promises they make when they enter into a trade

Recent controversies might make this seem hopelessly naïve – and they show that ensuring fairness in exchange is important – but assuring performance is the core of the aspiration.

And to deliver on this aspiration, today’s system is based on a closed, centralized model. I talked about it here and also argued  Mt.Gox model was even more centralized than the mainstream system.

We’re now seeing serious projects work on this problem. Perhaps revisiting the fundamentals will help us predict which of these projects will prevail?

Why do we have exchanges in the mainstream world?  There are lots of valid answers (liquidity, fairness, …) but none of this matters if you can’t be sure a trade you make will be settled. After all, what’s the point of agreeing a trade with somebody if they can just change their mind afterwards if it suits them?

In the mainstream world today, the general model for a stock exchange is one where it has members, who are the only entities allowed to trade on that exchange. These members are subject to strict rules. For example, the London Stock Exchange’s rule book has over 100 pages: http://www.londonstockexchange.com/traders-and-brokers/rules-regulations/rules-lse.pdf

Rule G5000 sums captures the critical function of the exchange for me:

G5000

“Obligation to settle: A member firm shall ensure that every on Exchange trade effected by it is duly settled.” Obvious, perhaps… but it needs to be said!

So the exchange helps ensure an orderly market by vetting and monitoring its members. This gives participants confidence: they don’t need to worry about who is on the other side of their trade. They know the trade they agree to will get settled. But other exchanges employ different models:

  • Prefund: Mt. Gox asked everybody to deposit their Bitcoins or fiat with them before they could trade. It guaranteed that trades executed on Gox would settle. Unfortunately, it only guaranteed they would settle on the books of Mt.Gox. As many people discovered to their cost, a settled trade on Gox was not the same as cash the bank or Bitcoins in their wallet
  • Escrow: The model I outlined in my piece earlier this year was essentially an escrow scheme. You place your Bitcoins beyond reach and they are either delivered back to you when your bid/offer expires or are delivered to the buyer. The trick here is in choosing the escrow “agent” (or agents…) carefully.
  • Clearing: This is how the The London Stock Exchange does it. In certain situations, members don’t even need to own the securities they’re selling at the time they trade them; they just need to make sure they deliver them as promised on the day of settlement. This model works because there is a closed group of trusted and well-known entities. However, there is clearly a risk: what happens if one of the participants goes bust between trade and settlement? That’s what a clearing house is there to solve, amongst other things. It keeps a close eye on its members, requires them to contribute to a “default fund” and steps in to make the other members whole if one of them fails.

Now, when we look at some of the most vibrant projects in the Bitcoin and cryptocurrency world, we see something interesting: a large number of them are working on representing non-crypto assets – such as securities – on the blockchain – They’re building out the vision of a decentralized general-purpose asset ledger.

There are two concepts we need to understand:

  • A token – something that represents an asset. Perhaps 100 shares of IBM Common Stock or ownership of a particular car.
  • An issuer – somebody that makes a promise to confer the rights and benefits associated with that asset to whomever holds it at any given point.

A concrete example: imagine I owned 10000 IBM shares (I wish…). I could issue them onto one of these platforms and publish the definition so others could see it and could see it was from me. I would, in effect, be making a promise:

“I will convey whatever benefits I enjoy through my ownership of these shares to whomever holds the token”.

So if I receive a dividend cheque, I pay it to the holder of the token. If you trust me to be good for this promise, you might be willing to purchase the token from me for $2m or so… the price of the IBM shares… owning the token would be just as good as owning the shares… and you could store it in your Bitcoin wallet and not have to deal with your broker any more!

Now, it is unlikely that you’d trust such a promise from me. But if was made by a major custodian bank you might. But note: you do have to trust the issuer.

So why bother? Why bother going to the trouble of building a decentralized asset ledger if you have to trust somebody at the end of the process?

For me, the answer is that this approach might allow increased competition between issuers. Furthermore, moving disparate asset registers (custody records, vehicle registration databases, etc) onto a common architecture might enable innovations we haven’t yet considered.   It’s too early to tell so we can all be grateful to the pioneers who are experimenting so we don’t have to.

I think there are three broad camps:

  • Coloring Bitcoins. Projects such as chromawallet and coinprism are working on systems to “tag” Bitcoins so that they can be tracked across transactions
  • New Protocols Running Over Bitcoin. mastercoin and counterparty piggy-back on Bitcoin’s peer-to-peer network, double-spend protection and consensus system but their tokens are essentially independent of Bitcoins. A counterparty token is not simply a “tagged” Bitcoin.
  • Entirely Separate Protocols. NXT and ethereum fit into this camp.

I have no particular insight into the structure of any of these projects so let’s assume they’re all run by capable, honest people and further assume that we’ll see a future where assets of all types, including securities, will be represented on a blockchain-like decentralized platform.

Then what? Presumably people will want to buy and sell…. To exchange.

And that’s where things get interesting… because we have to solve the performance problem.   We’re now in a decentralized, pseudonymous world… how do we ensure somebody who offers to buy an asset for a given price actually goes through with it and pays up?

What is the crypto-ledger rule G5000?

Is it possible to build a decentralized exchange on any of these platforms that has the strong performance guarantees we need? Can we build a decentralized exchange where a matched bid and offer inevitably lead to a settled trade?

It we look at our three models from previously, “clearing” isn’t going to work (it is, by definition, centralized and reliant on trusted identities). “Prefunding” is also problematic – what happens if the entity you sent your assets to disappears? So it looks like “escrow” is the only game in town.

Now, part of the solution already exists: we can construct “atomic” asset transfers using the Bitcoin protocol today. So I will assume exchanging payment and asset in a single transaction (“Delivery versus payment”) is achievable today on any of the platforms discussed above. But we need to get to a point where creating a valid transaction like this is inevitable once a bid and offer are matched.

Here’s where I think the state of the art is with the three approaches and it’s surprisingly different:

Coloring Bitcoins. The systems I’ve looked at don’t route bids/offers over the Bitcoin system so any matching will be done external to the platform. So it seems to me that “decentralized exchanges” on this model will have to require those posting bids or offers to demonstrate that they have placed the corresponding colored coins/Bitcoins in escrow with one or more acceptable third parties. There’s nothing that will do this automatically. So, it’s worth watchin firms like Xapo in the US and Elliptic in the UK. Professionally-run Bitcoin “cold storage vaults” such as these feel like “proto custodian banks” that could perform this function. The question is: can they devise a service that is sufficiently decentralized yet which still allows them to earn an income?

New Protocols Running Over Bitcoin. My understanding of these systems is that they embed bids/offers in the blockchain and have a protocol definition that means matches can be determined unambiguously. Furthermore, the act of making a bid or offer locks the associated assets until the trade is resolved or a bid/offer expires… automatic escrow, if you like. Assuming I am right, then this does appear to offer the “inevitability” promise that I think is so important. But it is at the expense of polluting the blockchain with bids/offers. It seems inelegant to me that one would store transient data (time-limited bids/offers) in such a permanent form of storage. But perhaps there’s no other way?

Entirely Separate Protocols. My working assumption is that NXT, too, works on the basis of bids/offers encumbering the associated assets until the outcome of the trade is resolved.  With Ethereum, the answer to every question is, of course, “it’s Turing Complete so of course you can do it” but I need to dig a little deeper to be sure….

 

Where is this going?

I think we’re going to see a market test: the colored coin approach is, in many ways, the most elegant as it uses the blockchain solely for storing/transferring the asset.   It means a range of exchange types can be trialled (escrow, pre-funding, reputation-based?)… but none of them will deliver full “inevitability” of settlement.  Perhaps consumers will care. Perhaps they won’t.

Projects like mastercoin and counterparty look able to deliver on the “inevitability” promise but will it be at the cost of blockchain bloat?

It will be an interesting few months ahead.

 

A final thought… What if we simply don’t worry about it and price it instead?!

The other approach is completely radical… instead of trying to force performance, why not model it as an option? We can think of somebody who posts a bid/offer but who then reneges as exercising an option to renege. This option clearly has value – if they would lose money by completing the trade as agreed, the option payoff is at least as much as they stood to lose! So is it possible to model the value of the option to renege and force participants to pay the option value up-front in order to post a bid/offer?

Unanswered questions: to whom would the price be paid? Is there any precedent for modeling the “option to renege” in this way? What would be the liquidity implications?

Conclusion

I said at the start of this piece that a new financial infrastructure is being built “hidden in plain sight”. For the reasons outlined above, I think the “exchange” aspect of this infrastructure still has a long way to go but we’re about to witness a fascinating experiment.

A Simple Explanation of How Shares Move Around the Securities Settlement System

I explained here how money moves around the banking system and how the Bitcoin system causes us to revisit our assumptions about what a payment system must look like. In this post, I turn my attention to securities settlement: if I sell some shares to you, how do they actually move from my account to yours? What is actually “moving”? What do I mean by “account”? Who is involved? What are the moving parts? 

I have argued for some time that the Bitcoin system is best regarded as a global, decentralized asset register and that some of the assets it could register, track and transfer could be securities (stocks and bonds). In this post, I go back to basics to explain what actually happens behind the scenes today and use that to think through the implications should schemes such as ColoredCoins.org or MasterCoin gain traction. I’ve discussed these systems in a couple of articles here (coloured coins) and here (MasterCoin).

As in the previous article, my focus is on imparting understanding by telling a story and building up a narrative.  This means some of the precise details may be simplified. So please don’t build a securities settlement system for your client using this article as your guide!

First, let’s establish some common ground.

Here are the simplifying assumptions I’m going to make:

  • I’m going to invent a fictional company called MegaCorp
  • I’m going to assume we start back in the days when certificates were in paper form. I’ll move to electronic systems later in the article but I think it helps first to think about paper – it helps us keep track of what’s really going on
  • I’m going to rewrite history to suit the story. If you’re a historian of finance, this article is not for you!
  • Finally, I’m going to assume that MegaCorp already exists, has issued shares and that they are in the hands of a large number of individuals, banks and other firms.  I’m going to assume you’re one of these owners. How these shares were issued would be a fascinating story itself but there isn’t space here to talk about corporate finance, IPOs and all the rest. Google it: “primary market” activity is a really interesting area of investment banking.

So let’s get started. You own some MegaCorp shares and you want to sell them.

Selling shares if everything was paper-based

So… you own some shares in MegaCorp and you have a piece of paper that proves it: a share certificate. You’d like to sell those shares. Now you have a problem. How do you find somebody who is willing to buy them from you?

I guess you could put an advert in the paper or maybe walk around town wearing a sandwich board proclaiming your desire to sell.  But it’s not ideal.

Figure 1 - buyerseller

Figure 1 The fundamental problem: how does a seller find a buyer or a buyer find a seller?

The obvious answer is that it would all be so much easier if there were a place – a venue where people commonly in the business of buying and selling shares could get together and find each other.  Happily, there are and we call such places stock exchanges. In the early days, they were simply coffee houses or under a Buttonwood tree in trading centres such as London. Over time, they became formalized. But the idea is the same: concentrate buyers and sellers in one place to maximize the chance of matching them with each other.

This adds a new box to our diagram: the stock exchange.

Figure 2 - exchange

Figure 2 A stock exchange brings buyers and sellers together to help them execute trades

There are still some problems, however. What if you’re just an occasional buyer or seller? Do you really want to have to trek to London or New York every time you want to buy or sell? And as an out-of-towner, do you really think you’d get a good deal from the locals who spend all their time there? You’d be completely out of your depth.  So you’d probably value the services of an intermediary – somebody who could go to the exchange on your behalf and get you the best deal they could. We call these people stockbrokers (or just brokers).  An example for retail investors may be Charles Schwab. An example for, say, pension funds might be Deutsche Bank or Morgan Stanley.

Figure 3 brokers

Figure 3 Brokers act on behalf of buyers and sellers

You’ll notice that “stock exchange” has become “stock exchange(s)”: this reflects the reality that there could be multiple venues you could visit to trade a particular share.  This creates opportunities for arbitrage (the price may be different at each venue) but we’ll ignore this from now on.

Now this works fine if there is lots of trade in MegaCorp shares: when my broker tries to sell, there will probably be somebody else who wants to buy.  But what happens if there are no buyers just then? Does that mean the share is worthless? Clearly not. So there’s an opportunity to somebody to make a living taking a bit of risk by buying and selling shares on their own account. Whereas a broker is acting in an agency capacity, this new person would make money from their wits: buying low and selling high with their own money. We call these people market-makers – since they literally create a market in the shares in which they specialize. We call firms like Goldman Sachs and Morgan Stanley broker-dealers because some of their subsidiaries engage in both broking and market-making in various markets.

Figure 4 market makers

Figure 4 Market-makers buy and sell shares on their own account, creating liquidity

Guess what: we still have problems! Remember: I’ve asked my broker to sell my shares for me but imagine they succeed.  Then what? We now have the tricky problem of settlement.  Remember: we’re still in the days of paper-based certificates.  So my broker has just sold my MegaCorp shares. Well… the buyer is going to want the certificate pretty soon.  And I would quite like the cash.

Now… I could just trust my broker.  I could leave the paper certificate in their hands and ask them to take receipt of the cash when the buyer’s broker hands over their cash.  But that means placing a lot of trust in that individual. And remember: I chose the broker because they could navigate the rough and tumble of the stock exchange, not because I trusted their book-keeping skills!

Worse, what happens if MegaCorp issues a dividend while the share certificate is in the hands of the broker? Do they really have the ability or inclination to collect the divident, allocate it to my account and report to me about this in a timely manner? Perhaps, but probably not.

But we still have the need for somebody to keep the certificate safe and to be on hand to give it to the purchaser if a sale takes place. It’s just that the skills needed by this person are completely different to those needed by the broker.  The broker needs to be able to negotiate the best price for me. But the person who looks after my certificate needs to be good with accounts, book-keeping, reporting and security.  After all, I’m trusting them with the safekeeping of my share certificate: it’s in their custody.  So we call these people custodians. Examples include State Street and Northern Trust, as well as divisions of Citi and HSBC, etc.

Figure 5 custodians

Figure 5 Custodians are responsible for the safekeeping of shares

So now, when my broker finds a willing buyer at the exchange, they can tell my custodian to expect to receive cash from the buyer’s custodian and to send the certificate to the buyer’s custodian when this happens.

And while the share certificate is sitting at the custodian, they can deal with all the tedious things that can happen to a share during its life: dividends, stock-splits, voting, …  It’s as if the shares need regular attention, like an old car that needs constant servicing: so we call this business the business of securities servicing.  The picture above shows a line from the buyer/seller to their custodians, because the custodian is working on their behalf. However, retail investors will probably not be aware of this relationship as their brokerage will manage the relationship on their behalf.

So… what have we achieved?  I can lodge my share certificate with a custodian, instruct my broker to sell the shares on my behalf by finding a willing buyer at a stock exchange and wait for the cash to arrive. We’re done!

Erm… not so fast.  There are still several problems.    The first becomes obvious when you think about how the picture I’ve described would work in practice. You have loads of brokers shouting at each other, making trades all the time. It would be completely chaotic yet, somehow, we need to get to a point where the buying and selling brokers agree completely on the details of the trade they just did and have communicated matching settlement instructions perfectly to the two custodians so they can settle the trade.  That’s not going to be easy.

In reality, there’s quite some work that must be done post-trade to get it to the point where it can be settled (matching, maybe netting, agreement of settlement details, agreeing on time and place of settlement, etc, etc).  We call this process clearing. (I wrote previously about a real-life example of spontaneous clearing at the world’s first-ever open-outcry Bitcoin exchange.)

And there’s a second, more subtle, problem: how does my broker know that the person they’re selling to is good for the cash? And how does the buyer know that my broker can lay their hands on the shares? In the model I’ve just described, they don’t.  Now, perhaps that’s not a problem: after all, smart custodians are only going to exchange shares and cash at the same time.  But it’s still problematic: sure… if the buyer turns out not to have the cash, I still have my shares… but I wanted to sell them! And the price may drop before I can find a replacement buyer.

A clearing house is intended to solve both these problems. Here’s how: after a trade is matched (both sides agree on the details), the information is sent to the clearing house by the exchange. And here’s the trick: as well as orchestrating the clearing process and getting everything ready for settlement, the clearing house does something clever: it steps into the middle of the trade.  In effect, it tears up the trade and creates two new ones in its place: it becomes my buyer and it becomes the seller to the buyer.  In this way, I have no exposure to the buyer: if they turn out to be a fraud, it’s now the clearing house’s problem.  And the ultimate seller has no exposure to me: if I turn out to be a fraud, the buyer still gets their shares (the clearing house will go into the market and buy them from somebody else if it really has to).  We call this “stepping in” process novation and say that the clearing house is acting as a central counterparty if it performs this service. As an example, the London Stock Exchange uses LCH.Clearnet Ltd as its clearing house.

Of course, this amazing service comes at a price: they charge a fee and, more importantly, impose strict rules on who can be a clearing member of the exchange and how they should be run. In this way, the clearing house acts as a policeman, ensuring only people and firms with a good track record and deep resources are allowed to participate. (I’ll leave to one side whether this privileging of one group over another is a net good or bad!)

So we can update our picture again:

Figure 6 clearing house

Figure 6 A clearing house manages the post-trade process of getting to a point where settlement can take place and often also acts as a central counterparty

We’re almost there… but there are still some loose ends.  To see why, consider this from MegaCorp’s perspective.  We’ve been talking about buying and selling their shares and this all happens without any involvement from them at all.  That’s fine in most circumstances but it does cause problems from time to time. Specifically, what happens when the company issues a dividend or wants its shareholders to vote on something?  How does it know who its shareholders are?  Imagine it knew I was a shareholder.  What happens after I’ve sold the shares using the system above to somebody else? How does the company get to hear about the new owner?

Enter yet another player: the registrar (UK) or share transfer agent (US). These companies work on behalf of the company and are responsible for maintaining a register of shareholders and keeping it up to date. If the company pays a dividend, these companies are responsible for distributing it.  They rely on one of the participants in the process to tell them about share transfer. An example of a registrar in the UK would be Equiniti.

Figure 7 registrar

Figure 7 A registrar (or stock transfer agent) keeps track of who owns a company’s shares on behalf of the company

Now, I assumed up front that we were using paper certificates. And it’s amazing how far you can go in the description without needing to bring IT into the narrative at all.  But, clearly, paper certificates are a complete pain.  They can get lost, you have to move them around, you have to reissue them if the company does a stock split, etc.  It would clearly be easier if they were electronic.

For any given custodian, it’s not a problem: they can just set up an IT book-keeping system to keep track of the share certificates under their safekeeping.  And this can work well:  imagine if the seller of a share uses the same custodian as the buyer: if the custodian is electronic, no paper needs to move at all! The custodian can just update its electronic records to reflect the new owner.  But it doesn’t work if the buyer and seller use different custodians: you’d still need to move paper between them in this case.

So this raises an interesting possibility: what if we had a “custodian to the custodians”?  If the custodians could deposit their paper certificates with a trusted third party, then they could transfer shares between each other simply by asking this “custodian to the custodians” to update its electronic records and we’d never need to move paper again!

And that’s what we have.  We call these organisations central securities depositories.  In the early days, they were just that: a depository where the share certificates were placed in exchange for an equivalent entry on the electronic register. The shares were, in effect, immobilized at the CSD.  Over time, people gained trust in the system and agreed that there really wasn’t any need for paper certificates at all… so we moved from immobilization to dematerialization.  The UK’s CSD is Euroclear (CREST).

This completes our picture (and notice how it is the CSD who informs the registrar when shares change hands… left as an exercise to a reader is thinking through what happens if shares change hands within the same custodian and what it means for the granularity of the data held by registrars):

Figure 8 csd

Figure 8 A CSD acts as the “custodian to the custodians”

This picture also introduces regulators, governments and taxation authorities, for completeness. However, I don’t discuss them here. I also don’t discuss what happens if you’re trading shares cross-border.

So now we have the full story: if I want to sell some MegaCorp shares, here’s what happens:

  • My shares start off in the account of my broker, who uses a custodian for safekeeping
  • The broker executes a sale at an exchange
  • The clearing house establishes everybody’s respective liabilities, steps in as central counterparty and orchestrates the settlement process
  • The buyer’s and seller’s custodians exchange shares for cash (“Delivery versus Payment”), utilizing the CSD if shares need to move between custodians as a result. Assuming so, the company’s registrar is informed.
  • Somebody probably has to pay some tax J

You’ll notice many parallels with the global payments system: lots of intermediaries and lots of specialists – all of them there for a reason but imposing costs nonetheless.

Now, I said I would use this narrative to discuss what it could mean for Bitcoin “colored coins”.  I think there are two key concepts that can help us think through workable models: risk and the meaning of settlement.

Risk

Consider the picture above: what risks are you exposed to as an investor? Ideally, if you buy shares in MegaCorp, the only risks you want to be exposed to are those associated with MegaCorp itself, realized through changes in share price or dividend payments. So, the ideal state is when you just face this market risk.  And that’s broadly what the system above delivers: by depositing your shares in a custodian bank, which should keep them in a segregated account at the CSD, you’re protected even if the custodian goes bust: your shares are not considered part of the custodian bank’s assets. So the only risk you’re exposed to beyond the market risk (which you want) is operational risk that the custodian makes a mistake. (I’ll ignore cash here but note that it’s typically not protected in the same way)

Now, when we look at “colored coin” share representation schemes, we see there is the notion of a colored coin “issuer”: somebody who asserts that a given set of coins represents a particular number of shares in a particular company.  So now we have a big question: who is this somebody?  This matters because if the “somebody” reneges on their promise or goes bust, you’ve lost your shares.

Now, if a colored coin scheme were “grafted on” to today’s system, it could work quite well if done right.  Imagine a firm wanted to offer colored coins representing 100 MegaCorp shares. They could open a custody account, fund it with 100 MegaCorp shares as “backing” and we’d be done: such firms could perhaps compete on the completeness of their transparency.  However, owners of colored MegaCorp coins would have counterparty exposure to this firm, which means the risk profile would be different (worse?) than if they simply owned coins in a regular custody account.

Interestingly, you can’t overcome the problem entirely by having a custodian bank be the issuer because it’s not obvious to me that a coloured MegaCorp coin issued by a custodian bank is the same as a segregated share for the purposes of bankruptcy protection: you’d presumably also need a legal opinion – and I am not a lawyer!

Bottom line: there is work to do for those developing these schemes.

However, there is one intriguing possibility with this approach: think through what happens if MegaCorp themselves were to issue colored coins representing their shares. Any analysis of counterparty risk becomes moot: if MegaCorp went bust, you’d lose your money regardless of how your shares were held!  Perhaps this is the future?  (Note also that I’m not discussing here precisely why anybody would want to issue – or buy – coloured coins! I’ll leave that to others)

Do you actually want settlement?

However, there’s another way of looking at this: you don’t have to own a share to enjoy the benefits of ownership. Contracts for Difference (or, more generally, Equity Swaps) allow you to enjoy the losses or gains from owning a stock without actually owning it. They are, instead, contracts, with a counterparty, in which the counterparty pays (or receives) cash that matches the gain or loss in the share price (and payment of dividends).   Now, the counterparty often hedges their risk by buying the shares – but that becomes their problem, not yours. So this gives you all the benefits of owning the stock without having to go through the pain of actually taking delivery. It also has tax advantages in some jurisdictions.

The downside is that you take on counterparty risk to the party issuing the CFD: if they go bust while you’re in the money, you’re out of luck.  But we’ve already established that there could well be quite considerable counterparty risk with colored coins in any case. So perhaps this is the right model.  I don’t yet have a view on which will prevail but hopefully laying out how today’s system is constructed will help others think this through more clearly.

I’ll end with one final observation: the issuance is the easy part.. but somebody still has to do the servicing.  But notice how this is much easier if you use a technology such as the Block Chain: there’s no need for the arbitrary distinctions between custodian, CSD and registrar:  the issuer can see immediately which addresses own their coins and to whom they should send messages or dividends.  Similarly, the peer-to-peer nature of Bitcoin means the hierarchy of custodians and CSDs could possibly be collapsed.

I know many people think blockchain technology could be hugely disruptive for the world’s banks but I look at it another way: I believe there are huge opportunities for those financial firms that really take the time to study this space.

[Final comment: a reminder to readers that this is my personal blog and the opinions are mine alone… I don’t speak on behalf of my employer]

[Update – 2014-01-07 – One question I failed to address above is precisely why anybody would want to settle share trades using a coloured coin scheme! I think there are two possible answers:

1) if settlement can be effected over the blockchain, the cost potentially reduces to the fee of the Bitcoin transaction in simple cases

2) if opens up the potential for custodians, CSDs and registrars/stock transfer agents to innovate their business models in a new way: do they still need to be separate entities, for example? Further, would ‘regular’ companies see value in becoming their own issuers, etc?

However, I’m not convinced this approach does anything to reduce risk – the challenge would be how to build a system with risk as good as what we have today. ]

Decentralised Digital Asset Registers – Concepts

I am hugely optimistic about the role cryptocurrencies (such as bitcoin) will play in the future – and one of the reasons is that they enable us to build decentralised digital asset registers.  I’ve written about this concept here.

In this post, I’ll explore some of the current thinking on how to build such a system.

The simplest way to think about this subject is to imagine you own one hundred twitter shares that you would like to sell and, because you’re one of these early-adopting trailblazers, you want to sell the shares for Bitcoins and want to do so using only the bitcoin system.  Here’s how it could work:

As I write, Twitter shares trade for just over $40, so your one hundred shares would be worth about $4000.  So you could announce to the world that a particular Bitcoin you own (strictly, a transaction output) is for sale and that you will give whoever buys it all the rights associated with the twitter shares… e.g. dividends, votes, etc.  You don’t plan to transfer the share through the regular equity settlement systems in your country, though; you’ll remain the registered owner there… but provided you are trustworthy, the recipient will trust you to pass on the benefits you receive to them.

A Bitcoin today trades for about $300.  So if you could find somebody who trusts you, they might be willing to pay you about $4300 for your special bitcoin ($300 for the Bitcoin plus $4000 for the rights to the shares).  Perhaps they’d demand a discount to account for the ongoing counterparty risk they have to you.  So let’s imagine they offer to pay you $4000 to keep the maths simple.

To make it interesting, let’s imagine that Alice is willing to buy 25% of your holding ($1000, or 3.33 XBT) and Bob wants 75% ($3000 or 10 XBT).  What we want is for them to transfer these coins to you and for you to transfer your “special” (or, colored) coin to them so that, once you’re done, you have 13.33 XBT and they have a share of the colored coin.

Graphically, this is what it might look like:

Colored Coin Diagram

In this picture, we see that a Bitcoin transaction has been constructed that has the following interesting properties (in reality, it may be done as a sequence of transactions and I’m not 100% sure you could actually do it this way for real on the current Bitcoin network but the concepts remain the same so we’ll stick with this for the purposes of this post)

  1. Alice and Bob pay their agreed amounts of Bitcoins into the transaction (i.e. their 25% and 75% share of the costs) – colored green in the diagram
  2. I pay in the coin I have previously asserted to be “equivalent” to 100 twitter shares – colored orange in the diagram
  3. Alice and Bob receive 25% and 75%, respectively, of the special (colored) coin so that everybody can now see that they are the owner of the coin, and hence entitled to their shares of any benefits associated with the shares – shown in orange on the right-hand side
  4. I receive Alice and Bob’s payments – shown in green on the right.

Easy, right? Well…. not quite.

The problem is step 3.  If you are an independent third party arbitrating a future dispute, how do you know that the 0.25 XBT and 0.75 XBT received by Alice and Bob relate to the ‘colored’ 1XBT I paid in?  What would have happened if I had also paid somebody else 0.75 XBT in that transaction? How would we know one of these payments was the special colored coin and one was just a regular bitcoin?

Worse, what would happen if Alice or Bob somehow temporarily forgot their coins were special and spent them as if they were normal coins? They could lose a fortune! It would be helpful if their wallet software warned them. Which means the wallet would need to be able to tell automatically. Worse, what if Bob used his colored coin as part-payment for a larger expense, with regular coins making up the difference?  How on earth would the recipient interpret their receipt of a transaction output that was formed from combining colored and non-colored coins?!

The answer is that there is nothing in the core bitcoin system that allows you to tell.  So various conventions have been proposed.  The simplest is one that just relies on ordering, but there are others, none of them particularly satisfactory.  But it’s being worked on.   I think one piece of work in particular has helped in this space by generalising this problem by introducing the idea of a “color kernel“, whose job it is to decide which outputs are related to which types of coin.  Projects such as bitcoinx are working on implementing a system based on these concepts.

In a future post, I’ll discuss a very different model, that of mastercoin.