For instance, he displayed a proficiency at golf quite unusual in men of athletic training, and they argued that any man who could do par whenever he felt like it must be either a professional or a person of limitless leisure.

And limitless leisure means limitless funds.
Gray studiously maintained his air of financial mystery; he was in and out of offices, always purposeful, always in a hurry, but always with sufficient time to observe the strictest niceties of polite behavior.
It was a part of his plan to create an atmosphere of his own, to emphasize his knack for quick, decisive, well-calculated action.

The money he received from Coverly enabled him to maintain the posture he had assumed; he spent it with his usual prodigality, receiving little direct benefit, but making each dollar look like four.

Extravagance with him was an art, money ran out of his pockets like water, but although he was already in a position to borrow, he did not do so.

He merely marked time, deriving a grim amusement at the way his popularity grew as his currency dwindled.