Struggling US department store chain Macy's said Monday that it has ended discussions with an investor group which sought to buy the company for roughly $6.9 billion -- after months of negotiations.

Macy's said its board of directors "has unanimously determined to terminate discussions with Arkhouse and Brigade," according to a statement.

"At this time, after careful review, we have concluded that Arkhouse and Brigade's proposal lacks certainty of financing and does not deliver compelling value," said Macy's lead independent director Paul Varga.

In March, Arkhouse Management and Brigade Capital Management upped their offer of $5.8 billion by offering $24 per share -- valuing the takeover at $6.6 billion.

It then raised its offer to $24.80 per share in cash, bringing the value to around $6.9 billion.

On Monday, Macy's said its board and management team engaged in "good faith" with Arkhouse and Brigade, providing documents with a level of detail going "well beyond what is customarily required to obtain financing for a public company acquisition."

This included store-by-store profit and loss information and leases for each location.

Macy's shares slumped 14.6 percent in pre-market trading on Monday.

Neil Saunders, managing director of GlobalData, said in a note that the news of talks ending "is to be welcomed."

"Other than seeking to monetize Macy's real estate assets for short term gain, neither party brought any long-term value to the table," he added.

Saunders noted that many of the activist investor proposals would also have "significantly weakened Macy's and hampered its ability to survive as a retail operation."

Department stores have seen their results suffer for years as consumers increasingly move online, and have been forced to reduce in size -- a dynamic worsened by the Covid-19 pandemic.

These trends have put pressure on shopping malls in the United States, especially older retail sites that have fallen out of favor.