Richard Lines, 60, former chairman and a founder of MTM, was convicted of two offences of conspiring to account falsely and one offence of making misleading, false or deceptive statements.
Thomas Baxter, 45, the company's former finance director, was convicted of one count of conspiracy to account falsely and another of making misleading, false or deceptive statements.
He was acquitted on a further account of conspiring to account falsely. Sentencing was deferred.
During the trial, which started in June, Vivian Robinson, for the SFO, said: "Lines and Baxter, assisted by others, cooked the books in order to give the impression that the company was a good deal more profitable than was, in fact, the case."