NEW YORK (AP) _ ''Serious Money,'' the British stock market satire about financial machinations, moves next month from off-Broadway to Broadway but without its English cast, Joseph Papp, head of the New York Shakespeare Festival, said Tuesday.

The play, written by Caryl Churchill, begins performances at Broadway's Royale Theater on Jan. 18. Casting for the American edition, which will be supervised by its original director Max Stafford-Clark, begins next Monday, Papp said.

''This is the first time a Caryl Churchill play has gone to Broadway,'' he said. ''She is kind of a social critic and I think one of the best writers in the English language.''

The transfer will cost about $700,000 with the money supplied by the Shubert Organization, which will be co-producing the play on Broadway with the festival, Papp said.

The play is an expensive show to operate, Papp said, with 16 actors plus a stage manager and will need to gross around $150,000 a week to break even.

The English company of ''Serious Money'' came to the Public Theater as part of a unique agreement between the Shakespeare Festival and London's Royal Court Theater which originally produced the play. The festival has sent such American productions as ''The Colored Museum,'' ''The Normal Heart'' and ''Tracers'' to London while the Royal Court has offered New York works such as ''Aunt Dan and Lemon'' by Wallace Shawn and Miss Churchill's ''Top Girls.'' Under the terms of the agreement, if the play runs longer than six weeks, it must be recast with local actors.

''Serious Money'' opened in New York on Dec. 3 at the festival's Public Theater to generally favorable reviews. The London production received an Olivier nomination - the English equivalent of the Tony award - as best play of the season.

''Serious Money'' is not the only off-Broadway hit transferring soon to Broadway. ''Sarafina 3/8,'' a South African musical, begins performances Jan. 19 at the Cort Theater after playing for three months at the much smaller Mitzi Newhouse Theater as part of the Lincoln Center Theater season.

The musical, written by Mbongeni Ngema and jazz trumpeter Hugh Masekela, uses Mbaqanga, black South African pop music. The show follows a group of black school children through one day, as they attend classes and battle with police.