The estate of Harper Lee has moved to end publication of a cheap paperback edition of To Kill a Mockingbird in the US.

According to emails obtained by the New Republic, Hachette, the US publisher of the mass-market edition of To Kill a Mockingbird, informed booksellers across America on 4 March that Lee’s estate would no longer allow publication of the mass-market paperback of To Kill a Mockingbird. The Hachette edition retails for $8.99, compared to the $14.99 and $16.99 larger trade paperback editions sold by HarperCollins, and has sold over 55,000 copies since the start of the year, more than double the sales of the trade paperback editions, the New Republic reported.

“The disappearance of the iconic mass-market edition is very disappointing to us, especially as we understand this could force a difficult situation for schools and teachers with tight budgets who cannot afford the larger, higher priced paperback edition that will remain in the market,” said the email from Hachette, which also claimed that “more than two-thirds of the 30m copies sold worldwide since publication have been Hachette’s low-priced edition”.

Lee died at the age of 89 on 19 February, leaving behind her the 1961 novel To Kill a Mockingbird, the Pulitzer prize-winning story of lawyer Atticus Finch’s courtroom battle to save a black man accused of rape by a white woman, and its sequel Go Set a Watchman. Published last year, the novel was actually written before Lee’s acclaimed debut, with her decision to release it after decades of silence greeted with controversy, although allegations of elder abuse against the writer were subsequently declared unfounded.

Last week, Lee’s will was sealed from public view by an Alabama judge, after lawyers for Lee’s attorney Tonja Carter – the “dear friend” who Lee had said in a statement “discovered” the manuscript of Go Set a Watchman – asked for the will to remain private.

According to the emails seen by the New Republic, the decision for Hachette’s mass-market edition of Lee’s debut to be discontinued was “per the author’s wishes”, although an attachment to the email said that “as of 4/25/16 there will no longer be a mass-market edition of To Kill a Mockingbird available from any publisher in the US as per the wishes of the author’s estate”.

A friend of Lee’s, Claudia Durst Johnson, author of Understanding To Kill a Mockingbird, told the New York Times that it made no sense for the estate to pull the edition to “make money at the expense of school children’s access to this classic”. “This book is a standard in our schools, which are struggling financially now,” she said.

A spokesperson for Lee’s publisher in the UK said that there would be no changes to publication of To Kill a Mockingbird in the UK.