News of the acquisition talks sent shares of GrubHub up nearly 30 percent Tuesday, but they slipped slightly by 3.7 percent Wednesday as details of firm numbers remained scarce.

Uber and Grubhub are still haggling over the deal’s stock exchange ratio, and there is no certainty that they will reach an agreement, sources told Reuters.

The ride-hail giant’s market cap sat just shy of $56 billion at Tuesday’s close, while GrubHub is valued at about $5.4 billion.

Uber “can wait a bit longer and probably get them cheaper. But it could be that you have a lot cats circling the same bowl,” Jesse Reyes, chief executive of J-Curve Advisors, who advises venture capital and private equity funds told Reuters.

A merger would see Uber take control of 55 percent of the food delivery market by buying market strength in cities like New York and Chicago, according to a Wedbush analyst note.

“This would be an aggressive move by Uber to take out a major competitor on the Uber Eats front and further consolidate its market position,” Wedbush analysts said.

Shares of Uber were down 1.2 percent Wednesday morning, at $31.98.

With Post wires.