Oct 6 (Reuters) - Major shareholders in music investor Hipgnosis Songs Fund are preparing to block the sale of a rights portfolio worth $440 million to a private fund owned by Blackstone, the Financial Times reported on Friday.

Hipgnosis announced last month it would sell 29 music catalogues, including songs by pop star Shakira and rapper Nelly, to a partnership between the company's investment adviser and funds advised by U.S. private equity group Blackstone .

Hipgnosis had said the deal would help fund a share buyback, pay down debt and bolster its stock price.

One of the top 10 investors in the company said that the price being offered by Blackstone was not high enough, according to the FT report.

The company declined to comment on the report.

Shareholders are also unhappy about a perceived lack of transparency over the costs of the deal, as well as the tax implications and the agreement that accrued income since the start of the year would go to Blackstone as part of the transaction, the paper reported, citing the investor.

The sale has a "go-shop" provision, meaning the board is entitled to solicit alternative offers for a period of 40 days from its announcement. (Reporting by Eva Mathews in Bengaluru; Editing by Saumyadeb Chakrabarty)