What it is:
How it works (Example):
For example, let's assume that a futures contract for shares of Company XYZ is three months long and is issued on April 1. The standard maturity date would be 90 days from issue, or July 1. However, if the contract has and odd date, it might mature on, say, June 28 or July 2. Alternatively, it might mature in, say, 5 weeks when the industry standard is 12 weeks.
Why it Matters:
The finance world depends heavily on standardized maturities for certain types of contracts. This in turn creates standardized recordkeeping and reporting for investors and the rest of the financial world, which makes trading easier and cheaper. When a contract has an odd date, it is something of a "rogue" investment and requires extra care both by the financial services firms involved and the investor who holds the security.