Millionaire's coin sale unsettles money market: A huge investment collection goes to Sotheby's tomorrow. Its sale could undermine world prices. Geraldine Norman reports

A COLLAPSE in the world market for Greek and Roman coins is expected to follow the sale of a vast collection built up by a rich Californian.

Experts believe that when the 45,000-strong collection of Bruce McNall, movie magnate, racehorse owner and coin enthusiast, comes on to the market, prices will plunge over the next year. The first instalment of the collection goes on exhibition at Sotheby's in London tomorrow.

The coins were amassed by two investment funds, Athena I and Athena II, launched by Merrill Lynch in New York in 1986 and 1988 respectively. Mr McNall managed both and was considered so vital to the funds' success that his life was insured for dollars 2m ( pounds 1.3m).

Athena I spent dollars 7.3m on coins and was so popular with investors that Athena II was launched two years later with the aim of spending a further dollars 25.1m on coins and antiquities. Each fund was expected to have a seven-year life, three years to buy and four years to sell again at a profit.

But selling has proved a problem. The two funds have about 45,000 coins to disperse. Some 3,500 will be on view in London before being auctioned by Sotheby's in Zurich on October 26-28. The rest will be split between New York sales in December 1993 and June 1994, while the antiquities are slipped unannounced into this autumn's property sales in London and New York.

All will be sold without protective 'reserves' - the technical term for minimum prices set by the owner below which no sale is permitted.

In theory, pounds 1,000 coins could be going for only pounds 5.

The Zurich sale will contain many great rarities most of which have already been offered for sale in Los Angeles by Numismatic Fine Arts, a coin auctioneering firm owned by Bruce McNall, where they failed to find buyers because of the reserve prices.

Mr McNall started dealing in coins as a schoolboy and founded the Los Angeles coin dealing and auctioneering firm Numismatic Fine Arts, as well as the Summa Galleries, now defunct, which dealt in antiquities. His coin dealing profits launched him into the business stratosphere.

He is only 43 and has been making films for more than 10 years; he owns the Los Angeles Kings ice hockey team, 60 per cent of the Toronto Argonauts football team and 200 race horses. His horses Trempolino and Samaurez won the Prix de L'Arc de Triomphe in 1988 and in 1990 respectively.

McNall has a way of finding very wealthy clients. He started with Sy Weintraub, the Hollywood mogul.

In 1979, he sold Weintraub's coin collection, at a big profit, to Bunker Hunt. Bunker and his brother Herbert Hunt, who inherited a multi-billion-dollar oil fortune, attempted unsuccessfully to corner the world silver market and ended up bankrupt.

McNall sold them some dollars 50m worth of coins and antiquities which were dispersed by Sotheby's on behalf of their creditors in 1990 at rock-bottom prices.

The huge prices paid by the Hunts in their heyday switched on the metal detector brigade across the Mediterranean. It has been estimated that the number of coins discovered in the 1980s matched the total number of coins previously known. Much of the new hoard ended up in the Athena funds. The greatest rarities in the Zurich sale appear to be recent finds.

The most romantic is a Roman aureus issued by Brutus, one of Caesar's assassins, to commemorate Caesar's murder and the Ides of March; it has a portrait head of Brutus on one side and a cap and two daggers on the other, with the inscription 'EID-MAR'. Only two such coins are known; this one turned up in the 1980s. It was offered for sale at Numismatic Fine Arts in 1990 and left unsold at dollars 550,000.

The sale contains four silver medallions, with the portrait of Berenice, wife of King Ptolemy III of Egypt (246- 221BC). They are among the largest and most spectacular coins struck in antiquity. Only one damaged example was known until the 1980s when a hoard of more than 20 was unearthed - apparently illicitly - in Egypt. The finest of the four was left unsold at dollars 105,000 at NFA in 1991.

Among the other excitements are a group of the very first gold coins ever issued. They date from the reign of King Croesus of Lydia (560- 546BC) - from whom the saying 'rich as Croesus' derives - and are decorated with a bull and a lion fighting.

There is also an exceptional group of heavy Roman gold portrait medallions and a tetradrachm from Syracuse, signed by Cimon, the Rembrandt of coin designers.

(Photographs omitted)