Jan Freeman remarked on Twitter that she had been hearing the phrase “on the up and up” meaning “improving” instead of “honest.”
There are indeed two general meanings of the phrase. The one I’m familiar with is “honest” or “on the level,” and the OED identifies it as originally American, with citations going back to 1863.
The OED doesn’t specify any nationality for the “Steadily rising, improving, or increasing” meaning. The first citation is from The Baltimore Sun, 1930: “From now on, we are led to believe, law and order will be on the up and up, as the current phrase is.” But that strikes me as ambiguous–that is, it could mean that law and order is on the level, as opposed to on the rise. All the other citations are from British sources.
But in any case, as Jan suggests, it’s now being used in the U.S., as in this from a March post in Forbes.com: “to say that Thrive [Capital] is on the up and up would be a massive understatement.”
Any Yanks out there who have a sense that “on the up and up”=”on the rise” is a long-term thing over here?