What happened

United Parcel Service (UPS 0.14%) stock was a winner on Monday, rising by 2.5% in price after encouraging news about an important labor negotiation hit the headlines. That performance easily topped that of the S&P 500 index, which saw a bump of barely over 0.1% on the day.

So what

UPS and the large, influential Teamsters union are currently locked in negotiations over a new contract for the company's workers. The current one expires on July 31, and both parties are eager to have an acceptable replacement before that date.

The latest offer from UPS was handed over Friday afternoon. Encouragingly, the Teamsters indicated that it was an improvement over the logistics giant's previous proposals.

"UPS came back with real movement, but it isn't enough," the union quoted its general secretary-treasurer Fred Zuckerman as saying.

"One of two things is going to happen next -- UPS will come to terms on a deal we can confidently recommend to our members, or UPS will fail, and the company will put itself on the street," he added. The union has said that, starting Aug. 1, its members at the company will not work without a new contract.

According to the Teamsters, UPS has promised to reach a deal with it by this Wednesday, July 5.

The contract covers anywhere from 330,000 to 340,000 workers employed at UPS, according to various estimates.

Now what

In an update published on its website Friday, UPS also sounded a note of cautious optimism, writing that it is "encouraged the Teamsters are ready to continue negotiations and discuss our most recent proposal... We look forward to the union's input so we can reach a timely agreement and provide certainty for our employees, our customers, and the U.S. economy."