FACTBOX: Firms exposed to Madoff's alleged fraud

(Reuters) - More firms around the globe disclosed they were caught up in the $50 billion fraud allegedly perpetrated by Bernard Madoff, a former chairman of Nasdaq. Madoff was arrested by U.S. authorities last week.

Following are some of the firms exposed:

* FAIRFIELD GREENWICH GROUP - The alternative investment specialist said in a statement on its website it had invested approximately $7.5 billion in vehicles connected to Madoff, or half of its assets.

* BANCO SANTANDER SA - Spain's largest bank said its investment fund, Optimal, has a 2.33 billion euro ($3.05 billion) exposure to Madoff Securities.

* TREMONT HOLDINGS INC - The hedge fund group's Rye Investment Management unit had virtually all of its assets invested with Madoff and lost roughly $3 billion, people familiar with Tremont said. Tremont is a unit of Massachusetts Mutual Life Insurance Co (MassMutual). MassMutual said its indirect exposure to Madoff funds was less than $10 million.

* ASCOT PARTNERS LLC - According to a Wall Street Journal report, the fund, where former GMAC chairman Jacob Ezra Merkin is a money manager, has an exposure of $1.8 billion.

* ACCESS INTERNATIONAL ADVISORS - According to a report by Bloomberg, Access has an exposure of $1.4 billion.

* FORTIS NV - The Dutch banking unit of the group recently acquired by the Dutch government said it may have a loss of up to 1 billion euros ($1.35 billion) due to loans made to funds that invested in Madoff Securities.

* HSBC HOLDINGS PLC - The banking and financial services group said it has potential exposure of $1 billion after providing financing to a small number of institutional clients who invested in funds with Madoff.

* BENBASSAT & CIE - The Swiss private bank has an exposure of $1.1 billion francs ($935 million), according to Le Temps. Benbassat said in a statement it is reviewing the potential damages caused to its clients. It gave no data but said the fraud appears "massive and spread amongst several large investor bases." Benbassat acts as a distributor of Thema International Fund PLC, an Irish registered fund that has invested in Madoff.

* UNION BANCAIRE PRIVEE - The Swiss bank that invests in funds of hedge funds has lost about 1 billion francs ($850 million), according to Le Temps, citing unnamed banking sources. UBP has so far declined to comment.

* NATIXIS SA - The French bank said it could have a 450 million euro ($602 million) indirect exposure to Madoff.

* ROYAL BANK OF SCOTLAND GROUP PLC - The bank said it had exposure through trading and collateralized lending to funds of hedge funds invested with Madoff, with a potential loss of around 400 million pounds ($598 million).

* BNP PARIBAS SA - France's largest listed bank said it has a potential 350 million euro ($464 million) exposure.

* SWISS LIFE - The insurer said its exposure to Madoff amounted to about 90 million Swiss francs ($80.07 million), or less than 0.1 percent of its assets under management.

* REICHMUTH & CO - Reichmuth & Co. said in a statement on Saturday the exposure of fund Reichmuth Mattehorn amounted to about 3.5 percent of its 11 billion assets, or about $325 million.