The resignation will take effect in December once Bloomberg LP closes its deal to acquire BusinessWeek from McGraw-Hill Cos. Adler joined BusinessWeek four years ago from The Wall Street Journal. He succeeded Stephen Shepard, who had been editor of the magazine for more than 20 years.

In his memo, which was posted on the BusinessWeek Web site, Adler wrote, “It was hugely important to me to help find the right home for BusinessWeek and to work closely with our business-side colleagues to ensure that staffers would be provided appropriate benefits under any circumstance. Now that these goals have been accomplished, I’m considering other opportunities, and I believe it makes sense for a new owner to move forward with a new editor.”