MADRID, Jan 13 (Reuters) - U.S.-based investment fund

Mason Capital said on Monday it had sent a letter to Spain's

stock market regulator CNMV demanding more transparency from the

embattled pharmaceutical company Grifols.

The activist fund said in a statement it had identified

potential conflicts of interest linked to related party

transactions by current board members, failure of internal

controls and a "rumoured clause" in a recent bond issuance that

benefits Canadian fund Brookfield at shareholders' expense.

"We urge the CNMV to consider the benefits to all Grifols

shareholders from improved disclosure," Mason Capital said.

The CNMV declined to comment about the letter.

Grifols shares were down around 3% in late afternoon trading

following the statement by Mason Capital, which owns a stake of

about 2.5% in Grifols.

In early January 2024, Grifols lost about a third of its

value in a few hours after short seller fund Gotham City

Research questioned its accounting and the size of its debt. The

share price has not fully recovered.

Barcelona-based Grifols denied any wrongdoing and sued

Gotham City. It also made a series of governance changes,

appointing a new CEO following the incident, and revised the

value of its debt.

In November, Brookfield dropped a plan to take over

the human-plasma drug developer, together with the founding

Grifols family, that valued it at 6.45 billion euros. The deal

fell through due to a disagreement over the valuation.