Matt Damon's agent no doubt sat up and paid attention yesterday morning when Forbes, the business magazine, pronounced his client to be a very particular sort of top movie star -- the one who provides the best return on the studio's investment.

That does not make him Hollywood's top celebrity -- that honour, Forbes decided a couple of months ago, belonged to Brad Pitt, both for his on-screen successes and the tsunami of media coverage surrounding his relationship with Angelina Jolie.

Nor does it make him the best paid actor in the business -- the likes of Will Smith, Tom Cruise and Leonardo DiCaprio easily outstrip him on that front.

If anything, it is precisely because he is not paid top dollar that he is so interesting, from a financial point of view.

A Matt Damon film, the magazine reported, will make back an average of $29 for every dollar the star is paid. That's roughly twice as much as Cruise or Tom Hanks. Pitt, who finished second on the Forbes list, will earn back about 24 times as much as he gets paid.

Not far behind him, tied for third place, are Johnny Depp, star of the monstrously successful 'Pirates of the Caribbean' series and Vince Vaughn, a comic actor with considerable domestic box-office appeal even if he is less well known overseas.

Below them come Jennifer Aniston -- a surprise, perhaps -- Angelina Jolie, Renee Zellweger, Reese Witherspoon, Ben Stiller and Sandra Bullock.

Like Damon, these are not necessarily the industry's top earners at all. No Julia Roberts. No Jim Carrey. No Russell Crowe -- who, according to Forbes, provides the worst value for money of any big star because his price tag is sky-high ($20m a picture or thereabouts) and his record on drawing in audiences middling to poor.

What they all have in common is that they are not grotesquely overpaid. Vince Vaughn will never be mistaken for a great actor, but his gentle (and occasionally not-so-gentle) comedies almost invariably draw a big domestic audience.

A lot of things about the Forbes list, like much else in the movie business, is of course a crapshoot. Damon happens to have been in two highly successful multi-film series, both of which scored big this summer: the 'Ocean's Eleven' series, in which he was merely a member of an all-star ensemble cast, not the lead, and the 'Bourne' series, whose third instalment, 'The Bourne Ultimatum', earned rave reviews and broke US box-office records for August when it made more than $70m on its opening weekend last weekend.

Damon also happens to have taken a punt on several low-budget films, working for a drastically reduced fee, that turned out to be critical and in some cases, box-office successes.

The biggest of these was Martin Scorsese's Irish gangster drama 'The Departed', set in Damon's home city of Boston, which turned out to be the director's biggest box-office hit ever, and earned him his first, highly elusive Oscar.

Damon himself would be the first to acknowledge that his run of success has been as much about luck as any brilliance on his part. Go back a few years, when he appeared in Robert Redford's expensive flop, 'The Legend of Bagger Vance', followed by 'All The Pretty Horses', Billy Bob Thornton's equally disastrous attempt, and the state of his career looked very different.

As Damon himself has told it, he did not receive a single film offer for six months. It wasn't until 'The Bourne Identity' became a big hit in 2002 that his career got back on track.

His career trajectory has not been entirely unlike that of his co-star in 'The Departed', Leonardo DiCaprio. Both had splashy entrances on to the Hollywood scene -- in Damon's case, when he co-wrote and starred in the Oscar-winning 'Good Will Hunting', in DiCaprio's when he starred in 'Titanic'.

Both then had fallow periods in which they were written off in some quarters as callow pretty-boys without range or depth. And both are now basking in a rare sort of critical and industry favour -- seen as highly talented performers who can also draw a large audience.

The only difference between them, in the end, is the money. DiCaprio is now solidly in the $20m per film bracket, while Damon's fee is closer to $10m. That's probably the one and only reason why Damon ended up topping the list and DiCaprio did not make the top ten.

One thing nevertheless quickly becomes very obvious -- that he has excellent taste in the projects he chooses.

From his first break-out role in 'Courage Under Fire' to his starring turn in the little-seen Terry Gilliam feature 'The Brothers Grimm', he has picked films that have all at least had the potential to be ground-breaking. Most remarkably, that's been true of his mainstream, popcorn choices as well as his more artsy ones.

Damon now has a clear choice. He can follow the time-honoured path of negotiating ever higher fees -- using his bankability as their number-one argument -- until he reaches the point where the return on the investment in him dwindles to a far more modest number. you might care to think of. Or he can settle for a little less, financially speaking and continue to make bold choices that will probably result in better movies. This second route is certainly the one that Damon has talked about taking.

- ANDREW GUMBEL