AT&T Inc. said on Tuesday it will spin off WarnerMedia in a $43 billion transaction to merge its media properties with Discovery Inc. and also cut its dividend by nearly half. AT&T shareholders will own 71 percent of the new Warner Bros. Discovery company and will receive a 0.24 shares of Warner Bros. Discovery for each AT&T share they own. AT&T will have 7.2 billion diluted shares outstanding after the transaction closes. The U.S. telecoms group will pay a dividend of $1.11 per share, down from $2.08 per share. This is at the lower end of an $8 billion to $9 billion range AT&T had forecast earlier. In premarket trading, AT&T shares were down 4 percent. The deal to unwind AT&T’s $85 billion purchase of Time Warner was announced early last year, but some financial details were not disclosed until Tuesday. “Rather than try to account for market volatility in …