The figure is expected to grow from 50,000 today to more than 500,000 in five years. But Elizabeth Gibling, of Chase de Vere Investments, warned savers not to be tempted into thinking Sipps was a cheap DIY alternative to traditional funds. 'Some areas being invested in are extremely specialist and should be left to experts,' she said. 'The number of people piling in is a cause for concern. Sipps can be a very good option but people should take advice before investing.'