NEW YORK—With the economy still reeling, the May sales in New York will fight a prevailing mood of uncertainty. "There’s caution on both sides, and sellers, buyers and the auction houses have to be realistic," says Guy Bennett, the head of the Impressionist and modern department at Christie’s New York. Overall estimates are a fraction of the houses’ combined expectations of $650 million a year ago. Still, the London sales’ low buy-in rates in February and the $266 million earned that month in the record Imp/mod session of the three-day Yves Saint Laurent-Pierre Bergé bonanza at Christie’s and Bergé & Associés, in Paris, have prompted a faint glow of optimism.

Sotheby’s kicks off the season with a lean and mean Imp/mod evening event on May 5. One of the month’s most expensive lots is a bronze cast of Alberto Giacometti’s rare-to-market attenuated Le Chat, 1959 (est. $16-24 million), which has been tucked away in a private European collection since 1967. The last time a cast from this edition of eight appeared at auction was in 1975, when it sold for $130,000, and most of the rest reside in museums, so anticipation for this piece is strong. The second major offering is Picasso’s Maya with Boat, 1938 (est. $16-24 million), depicting his daughter with his then-secret mistress Marie-Thérèse Walter.

Other lots to watch include Piet Mondrian’s sophisticated abstraction Composition in Black and White, with Double Lines, 1934 (est. $3-5 million), and Edvard Munch’s atmospheric Rowboats in Åsgårdstrand, 1932-34 (est. $1.8-2.5 million). Also in the sale are four Art Deco paintings by the Polish-born Tamara de Lempicka from the collection of the fashion designer Wolfgang Joop, including the fetching Portrait de Marjorie Ferry, 1932 (est. $4-6 million).

Stocking the sessions this year has been a challenge. "We know we have the buyers, but it’s been very hard to convince people to put works up at auction," says Emmanuel Di-Donna, the vice chairman of Sotheby’s Impressionist and modern department. "Hopefully, if the estimates are right, [the lots] should sell well." One strong candidate to do just that is Camille Pissarro’s landscape La Vallée de la Seine aux Damps, jardin d’Octave Mirbeau, 1892 (est. $1-1.5 million), which on its last trip to the block at Christie’s London in 2006, brought £960,000 ($1.8 million). "It’s a great buy for anybody," says Di-Donna.

Like the Sotheby’s session, the Imp/mod auction at Christie’s on May 6 is streamlined. "It’s a tighter sale than we’ve seen in past seasons," says department head Bennett, adding that it also offers a range of prices. At the lower end is Egon Schiele’s Liegende (est. $200-300,000), a 1918 drawing from the estate of the famed dealer and Viennese émigré Serge Sabarsky. Other works of notable provenance are Max Ernst’s Surrealist Malédiction à vous, les mamans, 1928 (est. $7-$9 million), which the consignor acquired in 1974 from Alain Tarica, the Geneva dealer from whom Saint Laurent and Bergé bought many pictures; and Picasso’s Femme au Chapeau, 1971, from the collection of the artist and filmmaker Julian Schnabel (est. $8-12 million).

Bracketed in price between the Schiele and the Ernst are Paul Gauguin’s early Nature morte aux tomates, 1883 (est. $1.75-2.25 million), and Henri Matisse’s pre-Fauve Nu à la serviette blanche, 1902-03 (est. $2-3 million), from the estate of the New York department-store heiress Caral Gimbel Lebworth. Also from this estate is the Giacometti lifetime cast Buste de Diego (stèle III), 1958 (est. $4.5-6.5 million).

Lempicka, whose sultry and stylized works seem to be the flavor of the month, is represented at Christie’s by the exceptional Portrait de Madame M., 1932 (est. $6-8 million). Consigned by a European vendor, the painting last sold at Sotheby’s New York in 1989 for $990,000. If it finds a taker here, it stands a fair chance of breaking the artist’s record, set at Christie’s in 2004, when Portrait de Madame Bush, 1929, made $4.6 million.