Hoyt Ammidon, one of the founding members of Grantchester Securities, a trading and research-oriented high-yield boutique that essentially closed last year, has started a hedge fund called Semaphore Management, according to high-yield sell-side officials. Ammidon's partner in the venture is Paul Carpenter, a former client of Ammidon on the buy-side. Ammidon has worked as an analyst and salesman. Prior to starting Grantchester, he worked at Salomon Brothers. Reached at Semaphore's office in New York, Ammidon declined to comment.