COB meaning in business: close of business
In business, COB means close of business, when the working day ends. A COB deadline means before the office shuts today. Dictionaries tie it especially to financial markets, where the close is a set time.
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COB as a deadline
What close of business means
COB is short for close of business, which means the end of the working day, especially on a financial market. “By COB” asks for the work before the office shuts today. “As of COB June 30” means the figures were taken at that day’s market close.
Among the deadline shorthands in our jargon dictionary, COB is the most formal. The oldest COB example one dictionary gives is from a 1997 membership directory.
Which hour COB lands on
COB is whenever the sender’s office closes, in the sender’s time zone. A COB set in Sydney falls before breakfast in London.
| Who | When their COB is |
|---|---|
| A trading desk | When the market closes |
| An office that opens at 8 | Maybe 4:30 |
| A support team on shifts | Possibly never |
COB, EOD and close of play
EOD is the same deadline, but tied to the end of the day instead of the office closing. EOW pushes it out to the last working day of the week.
British and Australian offices also say close of play, which comes from cricket, or end of play. 10.6% of Australian office workers say they use one of the two.
The other cobs
Corn, swans and bread rolls
In lower case, cob is a late Middle English word, first recorded between 1375 and 1425. It has several unrelated meanings:
- the core of an ear of corn
- a strong horse with short legs
- a small round loaf, in Britain
- a male swan, whose partner is called a pen
COB on an org chart and a circuit board
As an abbreviation, COB has other meanings too.
| Where | What COB means |
|---|---|
| A company | Chairman of the board |
| Electronics | Chip on board, an LED or chip bonded straight onto a circuit board |
| The US military | Contingency operating base |
| Insurance | Coordination of benefits |
Living with a COB deadline
The COB that arrives at breakfast
Work promised by COB can show up at 11:40 pm, because that’s technically still today. Or you get it at 8:50 the next morning, sent as “first thing”. To rule out both, ask for an hour as well as the COB.
A 5 pm countdown helps you meet a COB deadline only if the sender’s office closes at 5. If it closes at 4:30 or 6, count to that hour instead.
Asking for COB with an hour in it
Write an hour and a time zone next to COB, as in “COB Thursday, which for us is 4 pm Eastern”. It costs seven extra words and saves an argument. If a system sets the deadline, like a payment run or a courier pickup, say so, because a system closes on the minute.
When COB is also home time
On paper, close of business ends your day too. If someone says “leaving already” at 5:01, the answer is yes, said while walking. Leaving before COB takes a reason, and our excuses to leave work early are rated by the chance of a follow-up question from your manager.
On flex time, your close of business is the hour you picked.
The Friday COB
A request for COB Friday, sent at 3:55 that same afternoon, asks for your weekend. The sender logs off at 4. If the work could wait until Monday, say so.
Our how long until Friday clock counts down to your finish time once Friday comes.
A COB request by email
Subject: Supplier invoices for September
Hi Tom, please approve the three supplier invoices by
COB4 pm, before the payment run Thursday. Accounts closes the payment run at 4:30, and anything approved after that waits until October.
COB in a sentence
Please approve the budget by COB tomorrow.
Signed forms to me by COB Thursday, please. That's 5 pm London time.
Payments sent after COB are processed on the next business day.
The email landed at 5:52 pm asking for the deck by COB, Kasper. Does he mean eight minutes from now?
Questions about COB
What does COB mean in business?
COB is close of business, the end of the business day. "Approve it by COB" means before the office closes today. In a report, "as of COB" means the figures were taken when trading stopped.
What is the COB deadline?
A COB deadline is the end of the sender's working day, in their time zone. If the exact hour matters, as it does for a payment run or a filing, ask for it.
How is COB different from EOD?
COB is tied to the office shutting, while EOD is tied to the day running out. Most people mean the same deadline by both. Neither one names an hour, so write one in, with a time zone.
What does COB mean in the UK?
It means close of business there too, but British offices also say close of play, a phrase borrowed from cricket. In a British bakery or sandwich shop, a cob is a small round loaf.
Should I use COB or EOB?
Either one, since EOB, end of business, means the same deadline as COB, close of business. Use whichever your team already writes, and add an hour if it matters. Both have a second job in insurance, where EOB is an explanation of benefits and COB is coordination of benefits.
What does "respond by COB" mean?
Reply before the sender's working day ends, today unless the message names another day. "Respond by COB Thursday" gives you until their office closes on Thursday, in their time zone. If you can't make it, say so while they can still plan around it.