In "Contents of the Dead Man's Pocket," why does Tom go out on the ledge?

Tom Benecke risks his life by going out onto the ledge of his eleventh floor apartment because he desires business advancement above all else.
In his ambition for a promotion at work, Tom spends his free time and weekends on his new idea for "a grocery-store display method." One evening, rather than accompany his wife to a movie she had wanted to see, Tom decides to stay home and continue working on his project in the hope that it will lead to a promotion. If he finishes it before he returns to work on Monday, he can take it to his boss, who might read it over the weekend before seeing any other projects. 
Unfortunately, Mrs. Benecke's opening of the apartment door causes the warm air from the hall to enter the apartment. This rush of air passes through the room and lifts up Tom's yellow sheet from the desk. While Tom watches in dismay, the worksheet drops to the window ledge and slides out onto the ledge of the building. Desperately, Tom tries to reach it with his arms extended out the open window, but the yellow sheet is too far from him. Staring at the yellow paper for a long minute, Tom waits for it to move and fall to the street so that he can hurry to retrieve it. Unfortunately, the paper stubbornly sits on the ledge:

It was hard for him to understand that he actually had to abandon it--it was ridiculous--and he began to curse. Of all the papers on his desk, why did it have to be this one in particular!

This single yellow sheet contains the efforts of many lunch hours, four long Saturdays, "snatched half hours" at work, and many evenings at home. It would take months to redo this project. As Tom reflects upon all the hours he has spent toiling on this project, he realizes he cannot let the yellow sheet just lie there. To him, it represents a chance to become "a name in the minds of the company officials." Therefore, he decides to retrieve it by going out onto the ledge.

In the short story “Contents of the Dead Man’s Pocket” by Jack Finney, Tom Benecke goes out on the ledge of his apartment building to retrieve a piece of paper. It is not just any piece of paper; it is ledger containing the results of many months of personal market research Tom accumulated in hope of presenting new, innovative ideas to his bosses. He must decide whether the risk of retrieving the piece of paper is worth the reward.
The author alludes to a play on words by having Tom “go out on a ledge.” When one does that, they are generally putting themselves in a dangerous or difficult situation with the hope of receiving accolades or rewards for presenting an idea that goes against the mainstream. In this case, Tom goes out on the ledge of a building that is eleven stories above a busy New York City street.
As you read the story, you determine whether the risk was worth the reward for Tom’s escapades on that ledge.