It is unable to offer much more cash because it wants to keep its investment-grade rating, said Mr. Wasiolek of Morningstar. It can increase its bid a little bit, but it is going to have to come from equity, he said. This is close to the final offer, he said.

“We’re in overtime in the March Madness competition here for the Starwood title, with a minute or two left on the clock,” Mr. Wasiolek said.

A representative for the Chinese consortium declined to comment on Marriott’s revised bid.

Shares of Starwood gained 4.5 percent on Wednesday to $84.19. Marriott shares declined 1.2 percent to $72.30.

Traders are accounting for the additional value Starwood shareholders will receive from the previously announced spinoff of its time share business, which is to be merged with the Interval Leisure Group. That deal is worth about $5.83 a Starwood share, based on Friday’s close. Accounting for both the spinoff and the Marriott offer, Starwood shareholders would be looking at a value of $85.36.

A combination of Marriott and Starwood, whose brands include Westin and Sheraton, would create the largest hotel company in the world, with more than 5,500 owned or franchised hotels and 1.1 million rooms around the world. The deal is expected to be neutral to adjusted earnings per share in 2017 and 2018.

Over the weekend, Starwood signed up to manage two hotels in Cuba, becoming the first American company to do so in more 50 years. Mr. Sorenson was also in Cuba on Monday, alongside President Obama on his historic visit. It was there that he took the conference call with analysts to discuss the deal on Monday, and was met with a unique set of technical difficulties, as the line kept cutting out.

Marriott is the best long-term partner for Starwood, Harry C. Curtis, an analyst at Nomura, wrote in a note on Monday. If they go through with the transaction, the combined company will have the “largest hotel platform, which should help it capture more market share, as loyalty program conscious travelers are drawn to the most flexible and broadest system,” he said.