This deals with the sale value, I think what the OP may be after is the cost base of shares acquired as part of the MQG divestment. From my reading of the tax ruling this would be the market value at the time of divestment, i.e. $3.73
Cost base and reduced cost base of the SYD Securities
67. The first element of the cost base and reduced cost base of the units in SAT1 and the first element of the cost base and reduced cost base of the shares in SAL which comprise a SYD stapled security, are their market value (subsection 112-20(1), section 110-25 and section 110-55).
68. The market value of a SYD stapled security must be apportioned between the units in SAT1 and shares in SAL on a reasonable basis. The Commissioner accepts that it is reasonable to have regard to the net asset values of SAT 1 and SAL at the end of the month during which the Distribution was made.
69. The units in the SAT1 and shares in SAL were acquired by MGL shareholders on the Distribution Date (ie 13 January 2014). This is the time when MGL stopped being the owner of the units in SAT 1 and shares in SAL (item A1 (case 1) of the table in subsection 109-5(2)).