Individually expensed AI subscriptions — tools bought on personal cards and claimed back on expenses — have risen 108% year-on-year in spend, according to Marketing Signals' Subscription Creep Report. The tools are typically copywriting assistants, transcription software, and image generators costing between $20 and $40 a month each. Because they arrive as individual expense claims rather than procurement lines, virtually none appear in software budgets.
Between 50% and 71% of employees report using AI tools their employer has not approved, while separate research puts the proportion of executives who admit bypassing IT entirely to buy technology at 98%. ChatGPT is now the single most expensive individual software purchase identified in Marketing Signals' underlying data, ahead of any traditional SaaS product.
For marketing departments specifically, the agency estimates forgotten and unauthorised AI subscriptions cost UK businesses roughly £63.7 million a year, with a range of £34.0 million to £112.1 million. The wider waste picture is worsening: data from Vertice cited in the report shows combined SaaS waste has climbed from 62% to 65% of all licences over the past year, a period in which AI-native software spend accelerated sharply.
Harry Nisbet, General Manager at Marketing Signals, said the problem is consistently misread as a governance issue when it is really a financial one: "Everyone talks about shadow AI as a security problem, and it probably is one, but almost nobody's counting how much this actually costs businesses. A $20-a-month tool feels invisible on a personal expense claim, and that's exactly why it never gets reviewed or cancelled. Multiply that by however many people are doing the same thing across a business, and it adds up faster than most finance teams realise."
Nisbet added that his own agency's most recent internal audit identified five tools to remove or replace, cutting subscription costs from £1,875 to £713 a month — a saving of £1,100 monthly, or roughly £13,200 a year. The fix, he said, required no new software: a short conversation with each team member about what they were paying for out of their own pocket.
Marketing Signals has published a free calculator alongside the report, allowing businesses to model what subscription creep could be costing them based on the same national data. The full report, including AI-specific figures and methodology, is available at marketingsignals.com.
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