French telecom provider Iliad is reportedly planning to increase its $15 billion offer to acquire U.S. company T-Mobile, but is setting limits on their budget.

Earlier this month, Iliad offered the U.S. carrier $15 billion worth of cash, or $33 per share, to acquire more than half of T-Mobile's shares in order to prevent a potential partnership with Sprint. Eventually, the merger was cancelled after receiving opposition from certain competitors who argued that the merger will create an impossible competition in the market. By the end of the month, T-Mobile's parent company Deutsche Telekom reportedly discussed in a meeting that it might sell the company at $35 per share. During that time, Iliad did not comment if it plans to increase its bid.

Iliad CEO Thomas Reynaud said on Monday that they are in talks with different private equity firms and companies that want to be part of their acquisition deal with T-Mobile. However, he refused to provide more details about the matter, Reuters reported.

"The offer we made is still pertinent but it could evolve, not specifically in terms of valuation, but on the percent of the capital (that Iliad proposes to buy)," Reynaud said at a news conference.

When asked about Iliad pooling in partners for the acquisition deal, Deutsche Telekom said that the company is still waiting for an acceptable bid. Iliad, on the other hand, refused to comment of its next steps if ever it fails to finalize a deal with partners. The company is open for a higher bid, as long as it is still within a considerate value.

"Our offer has certain merits: It has no antitrust risk, is financed and offers a premium," said Mr. Reynaud, Iliad's finance chief, to the Wall Street Journal.

Meanwhile, Iliad's shares dropped by 8.7 percent, and investors feel that its U.S. foray is too risky and they prefer that the company concentrate on keeping the business in France.