Business writers write to inform, query and persuade. They write for action, not to say, hello, howdy do. Business readers read to answer the following questions:
Why did you write to me (your purpose)?
What do you want me to do (action)?
Why should I care (benefit)?
We write and read this way in business because none of us has time to waste. We are starved for time. Short words, short sentences and short paragraphs help the writer achieve his/her purpose; and, short words, sentences, and paragraphs help us, the readers, get the message (action/benefit)quickly.
Business readers appreciate the journalistic, "inverted pyramid," approach, that is, writing that offers the reader the who, what, when, where, why, how, and how much in the first sentence(s). In this style, an inductive approach, a message to your boss might begin by saying,
"We need $250,000 more for this project. With the new cash we will hire two more staff and buy another laptop. With those resources we will conclude the project two-weeks ahead of schedule. Moreover, we will achieve efficiency and give you a $100,000return."
No fooling around here (or "beating around the bush," as they say idiomatically)! Short words, short sentences.
You will note that I used four sentences in the example. However, when you keep the subject and verb together, preferably at the beginning of the sentence, and choose strong (action) verbs, you can write longer sentences. You can do this because readers, who need to find the subject and verb quickly, will be able to. The rest is just modification. So, the sentence above could easily look like this:
"I write to ask for $250,000 more for this project so that we may hire two more staff, buy another laptop, and conclude the project two-weeks ahead of schedule, creating a $100,000 return on the investment."
In that sentence, the subject "I" is followed immediately by the action verb "write," and the direct object "to ask." The main clause is, thereby, constructed as a S-V-O pattern. The dependent clause that follows is built from the same pattern. This makes the long sentence easy to understand.
However, many long sentences suffer because they use being verbs and, therefore, cannot use the S-V-O pattern. Look at the following sentence:
"This message, regarding a $250,000 investment in additional staffing and other resource allocation, is meant as an argument for conclusion of the current project by a two-week interval followed by the creation of a $100,000 return on investment."
That sentence doesn't help the reader who has to search for the subject ("message") and the verb ("is") and wade through a host of weak words (verbs that have been turned into nouns): "regarding," "investment," "additional," "allocation," "argument," "conclusion," "followed," and "creation." These words function as nouns, instead of the strong action verbs they could be. In this case the long sentence definitely doesn't work. And, truth be told, this writer wrote to impress, not express.
You make choices when you sit down to write. You can choose to write long or short sentences, but remember, if you write a long sentence, you must craft it carefully or you will lose the reader, who will likely need to read the sentence again, wasting time, or, worse yet, completely missing your meaning. Keep the subject and verb together, preferably at the beginning of the sentence, choose action verbs, and use characters as subjects ("I," "you," "the team," "the manager," "the client," "the boss," and so forth).