The reasons why are complex. Some would point out that the two retrospectives over-exposed his work. Others would say that Stella's paintings, especially his later ones, are too unwieldy to live with. Another group might claim that the artist changes his format far too often. The truth is that all three of these lines of thinking are correct.

However, the converse is also true. Who could argue with the massive attention a show at MoMA bestows on an artist? Who can fault an artist for being ambitious enough to tackle working on a tremendous scale -- along with all the expense and hard work that goes with it? And who can criticize a painter for continually pushing himself to reinvent his work?

The problem with the Stella market can also be partially blamed on the lack of a strong primary dealer. This can be traced to the artist's unhappiness with his initial representation by Castelli. Back in the early 1960s, it became apparent early on that Castelli's main artists were going to be Jasper Johns and Roy Lichtenstein -- not Stella. Castelli lavished the lion's share of attention on these two artists because he genuinely loved the work and it sold so well. Stella also proved salable, but apparently Castelli never developed a close rapport with him.

Eventually, despite unwavering support from Castelli, Stella probably felt slighted by not being top dog. He began developing a close relationship with the dealer Lawrence Rubin, the brother of MoMA curator William Rubin -- who had given Stella his retrospectives. Eventually, Stella worked out a solution that was beneficial to him but uncomfortable for Castelli.

Stella decided to allow Lawrence Rubin's Knoedler Gallery to co-represent him. The problem with that arrangement was that Knoedler had an exhibition space that was more suitable for 19th-century painting than contemporary art. Stella's work never looked quite right there, thanks to an unsympathetic space and the context of a gallery not solely dedicated to cutting edge art.

Additionally, there is the issue of scale. Although Stella never worked small, early on he did produce a fair number of paintings that were approximately six feet square. As time went on, he began a series of undervalued paintings called the Protractors -- some of which were in excess of 20 feet long. But at least the Protractors were still canvases.

During the 1970s, Stella began creating mixed media relief works, such as the equally undervalued Exotic Birds. The three-dimensional quality of Stella's paintings became more pronounced and, by the 1980s, extended several feet off the picture plane. Finally, in the 1990s, the work evolved into full-blown sculpture.

While it's an artist's prerogative to work on any scale which he deems effective, it is also a collector's prerogative not to buy work that is simply too overwhelming. That is essentially what happened to Stella's market -- many of the paintings have become impossible to live with. Yet, even the modestly sized ones from prime periods have had trouble finding buyers.

For example, at Sotheby's May, 1999, evening sale, a classic Concentric Square painting came up for sale. The picture was the ideal size (63 by 63 in.), from the 1960s, and was painted in a bright array of colors. It appeared to be in good condition and carried a right-on estimate of $200,000-$250,000. Inexplicably, the painting passed.

Other auction disappointments abound. Last year, a very beautiful small-scale (27 by 41 by 3 in.) Exotic Bird, Laysan Miller bird #22 1x, came up at Christie's (Nov. 2000) with an estimate of $50,000-$70,000. The work sold for a bargain $47,000. Another Exotic Bird, albeit a much larger one (107 by 129 by 17 in.), Green Solitaire (5.5x), came up at Sotheby's (Nov. 1999) and only brought $178,500 against a $150,000-$200,000 estimate.

In current terms, the winning bid for a Stella is what you might expect to pay for a good Julian Schnabel or less than half of what a good (but not great) Eric Fischl might bring. Schnabel and Fischl are respectable artists but, from a historical and quality perspective, they aren't in the same league as Stella.

Stella is rated a "Hold," which is to say that if you already own one you should probably hang onto it. If it's a first-rate example, chances are it can only go up in value. If you're thinking of buying, you should probably be looking at the smaller works, especially the Exotic Birds series. Some of these works are real stunners and will reward you with plenty of pleasure and, just maybe, an eventual good return on your investment.

Recommended reading: Working Space by Frank Stella.