He said the company was not prepared to build on the site on a purely speculative basis.

"We won't start on a 100 percent speculative basis," he said.

For most of the last four decades, office buildings and other commercial structures were built largely on a speculative basis.

In certain areas new construction also is taking place on both a build-to-suit and speculative basis.

On top of these fundamentals, other features make the company interesting on a more speculative basis.

Further phases are unlikely to be built on a speculative basis.

Most of it, he said, was built to the specifications of companies, rather than on a speculative basis.

As often happens in advertising, the agency had developed the campaign on a speculative basis.

It is most unlikely that the tower would be built on a purely speculative basis.

"So our strategy has been to build on a speculative basis."