TAIPEI, May 21 (Reuters) - Taiwan's central bank plans to require foreign investors receiving U.S. dollar-denominated dividends from companies including TSMC to stick with one currency choice and not switch frequently, with authorities currently leaning toward allowing changes only once a year, three sources familiar with the matter said.

Here are some details:

-- In April, Taiwan's Financial Supervisory Commission said listed local companies could begin distributing foreign-currency-denominated dividends to foreign shareholders.

-- The sources said foreign custodian banks were willing to cooperate with the new rules for U.S. dollar dividend payouts for Taiwan stocks.

-- One of the sources, who declined to be named as they were not authorized to speak publicly, added that allowing investors to change their selection once a year would be acceptable, but changes should not be made too frequently.

-- TSMC began paying quarterly cash dividends in 2019, distributing dividends four times a year.

-- Reuters could not immediately obtain an official response from Taiwan's central bank and TSMC.

-- Due to the time required for foreign custodian banks to build the necessary systems, actual implementation of foreign currency dividend payouts is expected to begin next year.