The agreement is subject to Overseas Investment Office approval and Spark has a 15-year agreement with TowerCo to access existing and new towers, with a development commitment of 670 sites over the next 10 years.
Greg Smith, head of retail with Devon Funds Management, said Spark has secured a "pretty good" price compared with similar asset sales across the Tasman.
"It was a pleasant surprise and the market responded. Spark will be able to take capital expenditure out of the sale price and funnel some of the windfall back to shareholders. It now has the capacity to increase the dividend."
Smith said the local market was anxiously waiting for the announcement from the Reserve Bank. "It's not so much about what is done – the bank is expected to raise the official cash rate (OCR) another 50 basis points – it's about what is said in the commentary about the economy and where the OCR will end up."
There were few movements among the leading stocks. Auckland International Airport was down 6c to $7.22; Mainfreight was up $1.08 to $71.98; and Restaurant Brands increased 36c or 3.34 per cent to $11.14.
Summerset Group Holdings fell 28c or 2.73 per cent to $9.97 after earlier telling the market that total sales of 232 for the three months ending June was down from 279 sales in the previous quarter.
Fellow retirement village operators Ryman Healthcare was down 18c or 2.03 per cent to $8.69, and Oceania Healthcare decreased 2c or 2.08 per cent to 94c.
Eroad's recovery came to a crunching halt, declining 11c or 5 per cent to $2.09. Pushpay Holdings was down 5c or 3.91 per cent to $1.23. South Port New Zealand fell a further 22c or 2.86 per cent to $7.48, after sitting at $9 in mid-May.
Energy stocks Manawa was down 12c to $6.20, and Vector declined 6c to $4.33. Utilities investor Infratil gained 14c to $7.99.
Vulcan Steel decreased 34c or 3.74 per cent to $8.74; Investore Property declined 5c or 2.96 per cent to $1.64; Scott Technology shed 7c or 2.4 per cent to $2.85; and Pacific Edge was down 2c or 2.82 per cent to 69c.
Under pressure SkyCity Entertainment picked up 3c to $2.60 as the operations of its Adelaide casino are subject to an independent review.
Skellerup Holdings gained 7c to $5.15; Hallenstein Glasson increased 13c or 2.43 per cent to $5.47; NZME rose 6c or 5 per cent to $1.26; Barramundi investment fund was up 2c or 2.47 per cent to 83c; and Evolve Education collected 3c or 4.11 per cent to 76c.
Other gainers were Tourism Holdings, up 3c or 2.42 per cent to $2.54; Michael Hill International collecting 3 or 2.48 per cent to $1.24; and The Colonial Motor Company improved 25c or 2.65 per cent to $9.70.
Me Today, which markets supplements and natural skincare care products, improved 0.004c or 30.77 per cent to 1.7c.
Booster Innovation Fund, up 2c to $1.33, has added agriculture technology firm CellCo to its portfolio of 24 early-stage companies with an initial investment of $125,000.
Transport and logistics software company Trade Window Holdings is raising up to $10m through a private placement and share purchase plan at a 30.7 per cent discount of 70c a share. Trade Window went into a trading halt and last traded at $1.01.
In the United States, Twitter fell 11.3 per cent to US$32.65 ($53.46) after Elon Musk terminated his US$44 billion takeover deal.