Spending is also a noun. A gerund used to be the way you nounify a verb. “Ad spending” is perfectly grammatical, unlike “ad spend”. This seems to be part of a

Spending is also a noun. A gerund used to be the way you nounify a verb. “Ad spending” is perfectly grammatical, unlike “ad spend”. This seems to be part of a broader trend, not just business. One group of pastor-students would talk about giving a “preach”. Drove me nuts.