(Reuters) - Bank of America Merrill Lynch, which has suffered a wave of senior defections to rival UBS in recent weeks, hit back by hiring one of the Swiss bank's top executives, Alex Wilmot-Sitwell, on Wednesday.

Wilmot-Sitwell's appointment as president of Europe and Emerging Markets, excluding Asia, at BofA Merrill came barely a month after the U.S. firm lost dealmaker Andrea Orcel to UBS, which he will be joining as co-head of the investment bank.

Wilmot-Sitwell, who was chairman of UBS investment bank, is expected to join BofA Merrill in coming months and will be based in London, according to an internal memo seen by Reuters.

Both Orcel and Wilmot-Sitwell were veterans of their respective banks before the moves. The hire of Orcel had been seen as a dramatic move by UBS, which has been working to turn around its investment bank after a series of setbacks.

His departure had left several big gaps at BofA Merrill after he shunned a promotion. Wilmot-Sitwell will now take on some of Orcel's former responsibilities in emerging markets, as well as taking on the top Europe job.

The Europe president role will be vacated by BofA Merrill banker Jonathan Moulds later this year, when he retires from the firm. Orcel had been offered that position.

Wilmot-Sitwell has held several senior positions at UBS in recent years, including as joint head of European investment banking and as Chief Executive of the Asia-Pacific region.

But in March, at the time Orcel's hire, Wilmot-Sitwell ceased to become a member of the group executive board at UBS, and no longer had managerial or operational responsibility.

UBS declined to comment.