To realize digital cash you need a payment network with accounts, balances, and transaction. That‘s easy to understand. One major problem every payment network has to solve is to prevent the so-called double spending: to prevent that one entity spends the same amount twice. Usually, this is done by a central server who keeps record about the balances.
In 2008, following the bankruptcy of Lehman Brothers, the venerable Reserve Primary Fund broke the buck: It held millions of Lehman's debt obligations, and panicked redemptions by its investors caused its NAV to fall to 97 cents per share. The pullout of money caused the Reserve Primary Fund to close and triggered mayhem throughout the money markets.
This is a bank run in the sense that there is a mismatch in maturities, and thus a money fund is a "virtual bank": the assets of money funds, while short term, nonetheless typically have maturities of several months, while investors can request redemption at any time, without waiting for obligations to come due. Thus if there is a sudden demand for redemptions, the assets may be liquidated in a fire sale, depressing their sale price.
Both accounts give you easy access to your money and a competitive interest rate on your balance. Federal regulations limit the number of transactions (transfers or withdrawals) you can make from a Money Market Account to just six per monthly statement period. While you will receive checks and a debit card for those transactions, you won't have access to the free online bill pay service that comes with an Interest Checking Account. Remember, deposits are always unlimited and don't count towards your six transaction limit.
Ultrashort bond funds are mutual funds, similar to money market funds, that, as the name implies, invest in bonds with extremely short maturities. Unlike money market funds, however, there are no restrictions on the quality of the investments they hold. Instead, ultrashort bond funds typically invest in riskier securities in order to increase their return. Since these high-risk securities can experience large swings in price or even default, ultrashort bond funds, unlike money market funds, do not seek to maintain a stable $1.00 NAV and may lose money or dip below the $1.00 mark in the short term. Finally, because they invest in lower quality securities, ultrashort bond funds are more susceptible to adverse market conditions such as those brought on by the financial crisis of 2007–2010.
The first decentralized cryptocurrency, bitcoin, was created in 2009 by pseudonymous developer Satoshi Nakamoto. It used SHA-256, a cryptographic hash function, as its proof-of-work scheme. In April 2011, Namecoin was created as an attempt at forming a decentralized DNS, which would make internet censorship very difficult. Soon after, in October 2011, Litecoin was released. It was the first successful cryptocurrency to use scrypt as its hash function instead of SHA-256. Another notable cryptocurrency, Peercoin was the first to use a proof-of-work/proof-of-stake hybrid.
In 1998, Wei Dai published a description of "b-money", characterized as an anonymous, distributed electronic cash system. Shortly thereafter, Nick Szabo described bit gold. Like bitcoin and other cryptocurrencies that would follow it, bit gold (not to be confused with the later gold-based exchange, BitGold) was described as an electronic currency system which required users to complete a proof of work function with solutions being cryptographically put together and published. A currency system based on a reusable proof of work was later created by Hal Finney who followed the work of Dai and Szabo.
You don‘t need to understand the details about SHA 256. It‘s only important you know that it can be the basis of a cryptologic puzzle the miners compete to solve. After finding a solution, a miner can build a block and add it to the blockchain. As an incentive, he has the right to add a so-called coinbase transaction that gives him a specific number of Bitcoins. This is the only way to create valid Bitcoins.
This flexibility makes Ethereum the perfect instrument for blockchain -application. But it comes at a cost. After the Hack of the DAO – an Ethereum based smart contract – the developers decided to do a hard fork without consensus, which resulted in the emerge of Ethereum Classic. Besides this, there are several clones of Ethereum, and Ethereum itself is a host of several Tokens like DigixDAO and Augur. This makes Ethereum more a family of cryptocurrencies than a single currency.
In general, the NAV will stay close to $1, but is expected to fluctuate above and below, and will break the buck more often. Different managers place different emphases on risk versus return in enhanced cash – some consider preservation of principal as paramount, and thus take few risks, while others see these as more bond-like, and an opportunity to increase yield without necessarily preserving principal. These are typically available only to institutional investors, not retail investors.
If this sounds similar to banks’ high-yield savings accounts or money market accounts, it is. The largest difference lies in the ability for yields on money market mutual funds to rise proportionately with interest rates. For example, as interest rates have risen, the yields on most bank money market accounts (which are set by the banks themselves) have stayed relatively flat, while money market mutual fund yields have increased.