MADRID, Jan 17 (Reuters) - The European Central Bank has asked some lenders to detail their exposure to Spain's Grifols and its related entities, after the drugmaker was last week accused of manipulating its financial accounts by a short-seller, sources said.

Grifols denies the accusations by Gotham City Research that it has manipulated its debt and earnings through transactions with a related entity, to the effect that its leverage ratio is nearly double what Grifols has reported.

The ECB has in recent days contacted a number of banks to get them to outline their current exposure to Grifols and a network of connected companies, three sources with knowledge of the matter told Reuters.

The Barcelona-based pharmaceutical company has net financial debts of 9.5 billion euros ($10.3 billion), according to company data published in September, with 1.8 billion euros of that due next year.

The lenders contacted include Spanish and other euro zone banks, one of the sources said, speaking on the condition of anonymity because they were not authorised to speak to the media.

Supervisors want to have a better feel for exposure, the source said.

The ECB, which supervises larger banks in the euro zone through the Single Supervisory Mechanism, declined to comment.

Grifols has not disclosed which banks it and related entities owe money, and it declined to comment when contacted by Reuters.

Lenders to Grifols include Santander, BNP Paribas , Bank of America, BBVA and Caixabank , data compiled by LSEG shows.

All of the banks declined to comment.

Grifols, which makes medicines from human blood plasma, says it will partly depend on the sale of a stake in Shanghai RAAS Blood Products to repay the debts due next year, but that the deal to sell to China's Haier Group is on track.

REPUTATIONAL DAMAGE

Analysts have said concerns about the reliance on that deal and the reputational damage from the allegations have kept Grifols' shares under pressure following last week's rout.

Since Jan. 9, the stock has lost nearly 40%. Gotham's report has wiped more than 3.3 billion euros from Grifols' market value.

Central to Gotham's allegations is that while Grifols has included satellite companies' earnings in its accounts, their debts are not, and that if they were they would add to its debt burden.

Grifols says all its accounts have been audited and signed off by regulators.

The ECB is keen to understand banks' exposure to Grifols and companies partially controlled by the founding Grifols family including Scranton Enterprises, one of the sources said.

Supervisors are concerned that the tumble in Grifols' shares could require family-connected companies which have borrowed loans collateralised with Grifols shares to post more margin, the source said.

Grifols' CEO Thomas Glanzmann last week said that the family holds less than 20% of Scranton and that interactions between Grifols and Scranton have been made "at arm's length".

In its consolidated 2021 annual report, Scranton said it had outstanding loans to lenders including Caixabank, BBVA, Bank of America and BNP Paribas.

Spanish bank Santander in 2022 lent Quadriga Real Estate 250 million euros collateralised with 5.86% of the shares in Grifols, data from the Spanish official business register show. Scranton says it consolidates Quadriga's assets in its accounts as it controls 100% of the real estate vehicle.

Scranton did not respond to a request for comment. Santander declined to comment. ($1 = 0.9218 euros) (Reporting by Jesús Aguado; Editing by Tommy Reggiori Wilkes and Emelia Sithole-Matarise)