NEW YORK (Bloomberg) — Tyco International Ltd., the world's largest maker of security systems, increased the size of its planned debt sale to $750 million of ten-year notes, according to a person familiar with the offering.

The notes may pay a yield of 8.5 percent, said the person, who declined to be identified because terms aren't set. Tyco previously marketed $500 million of the debt.

The notes may contain a put that would allow holders to sell the debt back to the company on July 15, 2014, with 45 days notice, the person said.

The debt may be rated Baa1, the third-lowest level of investment grade, by Moody's Investors Service and an equivalent BBB+ by Standard & Poor's, the person said.