I know some companies or entities have large incomes or expenses at certain times of the year, and like to close their books after these large events.
For example where I work, the primary seasonal income comes after summer, so our fiscal year ends at the last days of October.
This gives the accountants enough time to collect all the funds, reconcile whatever they have to, pay off whatever they have to and get working on a budget for the next year sooner than a calendar year would.
There also might be tax reasons.
To get all of your income at the beginning of your fiscal year, even if that is in the middle of the calendar year would allow a company to plan large deductible investments with more certainty.
I am not to sure of the tax reasons.
money.stackexchange.com/users/91/MrChrister
I can think of a few good reasons: A company, especially public, usually wants their fourth-quarter earnings to be the strongest of the year.
That ends each fiscal year on a high note for the company and its investors, which helps public sentiment and boosts stock prices.
So, travel agencies and airlines usually like ending their year in October or March, in the lull between the summer and winter travel seasons with a large amount of that revenue falling within the company's fiscal Q4.
Oil companies sometimes do the same because fuel prices are seasonal for much the same reasons.
The downside of the above approach is that you make or break your entire year on your last quarter, which can cause problems for companies with scheduled dividends.
Usually that's not a huge concern, as dividends are based on profits, so if there aren't any profits there aren't any dividends.
However, in such cases a bad Q4 which also sends the entire company's year into the red is a double-whammy for stock prices.
If this is a concern, a schedule with strong Q1 and Q3 earnings, with decent Q4 (second or third-best season) and a "dump" in Q2 (weakest season) is typically the best overall bet.
December is a really bad month to try to close out an entire year's accounting books.
Accountants and execs are on vacation for large parts of the month, most retail stores are flooded with revenue (and then contra-revenue as items are returned) that takes time to account at the store level and then filter up to the corporate office, etc etc.
It also doesn't tell the whole story for most retail outfits; December sales are usually inflated by purchases that are then returned in January after all the hullaballoo.
As a result, a fiscal year end in January or even February keeps the entire season's revenues and expenses in one fiscal year.
The downside of the above is that a February fiscal year-end normalizes your December earnings.
Investors expect bad Q1 reports for most retail; consumers are looking at credit card statements and tightening belts.
Conversely, investors expect huge calendar Q4 numbers; to lump some of the bad news of returns and lower revenues in with your best sales quarter may cause you to continually fail to meet speculator's expectations which will cause your stock to be devalued relative to competitors.
money.stackexchange.com/users/4637/KeithS
My grandfather owned a small business, and I asked him that very question.
His answer was that year-end closeout is very time-consuming, both before and after EOY (end of year), and that they didn't want to do all that around Christmas and New Year.
money.stackexchange.com/users/22266/RonJohn
Maybe it's just because of the foundation date.
If I start a company on August 1st, I would like its FY starts on that date too, in order to track my first whole year.
Would be quite useless to finish my year on December, after just five months.
I want to have data of my first year after a twelve months activity.
money.stackexchange.com/users/46000/Dani
In addition to the company-specific annual business cycle reasons and company-specific historical reasons mentioned in the other answers, there is another reason.
Accounting firms tend to be very busy during January (and February and March)
when most companies are closing and auditing their calendar-year books.
If a company chooses its fiscal year to end at a different time of year, the accounting firms are more available, and the auditing costs might be lower.
money.stackexchange.com/users/26623/Jasper
There are many companies that have their year end occur on dates other than December 31.  What are the advantages to this?
Why do companies have a fiscal year different from the calendar year?
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<taxes><corporate-earnings>
money.stackexchange.com/questions/1002
money.stackexchange.com/users/19/Zephyr
Companies generally want their fourth quarter to be their strongest so this tends to influence the end of year date. Some companies have large incomes or expenses at a specific time of year, so will close their books after this. Accounting firms might also be more available if a company closes it's books at another time of year than December. It also depends on the date the company was founded. The answer will depend on the company's circumstances. However, some companies will want their fourth-quarter to be their strongest quarter. Other companies will want their first quarter to be the strongest so that they can plan investments. Other reasons could be related to tax implications or the availability of accountants during holiday periods.
Many companies want their fourth-quarter earnings to be their strongest. Because of the holidays, December is often a very impractical time to be closing accounting books. The company's tax year may simply depend on when the company was founded. There may be tax reasons for closing a company's yearly books on a specific date. If a company receives the bulk of its income at the beginning of its fiscal year, this will allow it to plan investments with more certainty.