* Bank to decide next month whether to do Swiss bank IPO - sources
* Currently plans to sell up to 30 pct of Swiss bank in H2
* But doubts are growing whether IPO will go ahead
* Accelerated bookbuilding and capital hike mooted alternatives
By Joshua Franklin and Pamela Barbaglia
ZURICH/LONDON, March 17 (Reuters) - Credit Suisse's board of directors is set to decide in April whether to go ahead with a partial initial public offering of its Swiss bank, two people familiar with the matter told Reuters, with alternative options being considered.
Zurich-based Credit Suisse announced plans to sell 20-30 percent of its highly profitable Swiss business back in October 2015, partly in an effort to raise up to 4 billion Swiss francs ($4 billion) and bolster the group's capital position.
However, group Chief Executive Tidjane Thiam cast doubt on the project last month when he said Credit Suisse was open to alternative options to strengthen the group's balance sheet "if there are ways to reach a more attractive risk/reward outcome for our shareholders".
No final decision has yet been made on whether or not go ahead with the IPO, the people said. Credit Suisse has pencilled in the IPO for the second half of this year, market conditions permitting and subject to board approval.
A Credit Suisse spokesman said the bank has nothing to add to what was said last month and it does not comment on market speculation.
Credit Suisse staff, one of the people said, are continuing to prepare for the IPO, which could be Switzerland's biggest stock market listing in more than a decade if it goes ahead.
However, there is a growing sense inside the bank and among investment bankers hoping to work on the listing that the IPO will be cancelled.
"Our internal language has changed," said one Credit Suisse executive, who declined to be named absent authorisation to speak publicly on the subject. "The nuance has changed to put more question marks around it."
Investors have also raised concerns about selling a stake in such a profitable business.
David Herro, chief investment officer for international equities at Harris Associates, one of Credit Suisse's biggest shareholders, said last month that the case for the IPO had become less convincing.
To boost its balance sheet, Credit Suisse could instead opt for a 5 billion franc rights issue, Bernstein analysts predicted in a note last week.
In a note this month, Citi analysts said Credit Suisse could raise funds through an accelerated bookbuild. Under Swiss securities law, companies are not required to draw up a listing prospectus if it is increasing its share capital by less than 10 percent.
"The IPO, rights issue or accelerated book-build are all possible options at this stage," one of the people familiar with the matter said.
($1 = 0.9976 Swiss francs)
Additional reporting by Arno Schuetze in Frankfurt and Oliver Hirt in Zurich; Editing by Michael Shields