"company is" and "company are"
(group names, also called collective nouns, group nouns, and nouns of multitude)

The AUE FAQ, under the heading "company is" vs "company are", says:

     Use of a plural verb after a singular noun denoting a group of
     persons (known as a noun of multitude) is commoner in the U.K. than
     in the U.S.  Fowler wrote:  "The Cabinet is divided is better,
     because in the order of thought a whole must precede division; and
     The Cabinet are agreed is better, because it takes two or more
     to agree."

The following is adapted from remarks by Markus Laker, with some editing to remove dependence upon a different context:

A number of people have hinted that British English differs from American English in the use of group nouns. Here's a British answer.

If you treat 'government' as singular, it means you're considering the actions of the government as a whole. So 'the government is killing the people' means that the government is, for example, ordering the army to kill people, or withholding food so that people starve to death.

If you treat 'government' as plural, it means you're considering the individual members of the government. So 'the government are killing the people' means that the members of parliament are going out at night with knives and guns and murdering people one by one. This probably isn't what you mean.

A number of other nouns, such as 'team' and 'committee', behave in the same way as 'government'.

Compare this with the following discussion taken from Bergen and Cornelia Evans's A Dictionary of Contemporary American Usage under the heading 'group names':

[Words typified by herd, flock, crowd, jury, family, nation] when used in the singular may be followed by either a singular or a plural verb. When what is said applies to the group as a whole, a singular verb is used, as in my family is a large one and the jury was out for six hours. When what is being said applies to the individual members of the group, a plural verb is used, as in my family are early risers and the jury were unable to agree. In general only the speaker knows which form suits his meaning best.

The singular group name with a plural verb is used in England more often than it is in this country. Very few Americans would say the herd were thirsty. But this is permissible grammar for anyone who cares to use it.

(The Evanses go on to discuss several other considerations involved in the use of group names, such as when to use who and which, the varying opinions of grammarians as to whether or not it's permissible to use a group noun as plural and singular in the same sentence, the use of group names with a preceding numeral, and the existence of certain nouns which are not group names but are used in the same manner. An example of the last is percent.)