Many of my personal shareholdings are FTSE 250 stocks. I believe the mid-cap index is home to some great UK businesses. However, there are at least two FTSE 250 shares I’ve already decided I won’t buy in 2025.

Wonderful product, terrible business?

I’ve never owned an Aston Martin Holdings‘ (LSE: AML) created car. But I have to admit I might be tempted if the opportunity arose. Call it a guilty secret.

One thing I don’t feel guilty about is my decision to avoid Aston Martin shares ever since the company listed in 2018. The stock’s lost more than 90% of its value over this time.

The upmarket sports car maker has already gone bankrupt seven times in its history. This time round it’s been kept afloat by billionaire chairman Lawrence Stroll’s ability to raise funds from new investors. But the picture still isn’t pretty.

Although Aston Martin’s annual revenue has risen by 50% to £1.6bn since its listing in 2018, the company still hasn’t reported an annual profit.

Cash continues to flow out of the business and net debt has reached £1.2bn. That looks scary to me. And City brokers expect the business to report further losses in 2024, 2025 and 2026.

Don’t get me wrong. Stroll’s strategy of aiming upmarket and building exclusive high-end cars may yet deliver Ferrari-style profit margins and big gains for shareholders. After all, Aston Martin’s a storied name whose cars also benefit from access to Mercedes-Benz technology.

This story may (eventually) have a happy ending. But nothing that could happen in 2025 will change my view that this carmaker’s simply too risky for me.

These boots are made for walking

My second pick is a company whose products are owned by members of my household and were the height of fashion when I was at school. Bootmaker Dr Martens (LSE: DOCS) can trace its history back to 1901, but has fallen on hard times since its flotation on the UK stock market in 2021.

The IPO was priced at a level that suggested growth would remain strong. Unfortunately, this didn’t happen. Dr Martens shares now trade more than 80% below their IPO price.

The slump in profits can be traced to two main problems. Firstly, consumer spending’s come under pressure, limiting the company’s ability to pass on higher costs.

At the same time, a botched effort to ramp up US growth has left the company with too much unsold stock and some big extra costs.

Pre-tax profit peaked at £214m in the 21/22 financial year and has fallen every year since. City analysts expect this year’s figure to be just £38m.

In fairness, Dr Martens is a stock I might consider owning in the right circumstances. I reckon it’s a decent brand that could keep performing. City analysts also expect its profits to stage a recovery next year. They’ve pencilled in an 82% rise in earnings to 5.6p per share. If the company hits that, the stock might not be too expensive.

For me, it’s too soon to make a call given the scale of recent problems. I’ll monitor progress for at least another year before reviewing this stock as a possible investment.