632. Authority for purchase of own shares
(1) A limited company may only purchase its own shares—
(a) by an off-market purchase, authorised in accordance with section 633 or in pursuance of a contract approved in advance in accordance with section 634,
(b) by a market purchase, authorised in accordance with section 641.
(2) A purchase is "off-market" if the shares either—
(a) are purchased otherwise than on a recognised investment exchange, or
(b) are purchased on a recognised investment exchange but are not subject to a marketing arrangement on the exchange.
(3) For this purpose a company's shares are subject to a marketing arrangement on a recognised investment exchange if the company has been afforded facilities for dealings in the shares to take place on the exchange—
(i) without prior permission for individual transactions from the authority governing that investment exchange, and
(ii) without limit as to the time during which those facilities are to be available.
(4) A purchase is a "market purchase" if it is made on a recognised investment exchange and is not an off-market purchase by virtue of subsection 632(2)(b).
(5) In this section "recognised investment exchange" means an investment exchange so determined in rules made by the Board.