Startups can raise capital at various stages of their development, from pre-seed to IPO. Here's a brief overview of the different stages and how startups can raise capital:

Pre-seed: In the pre-seed stage, startups are typically in the very early stages of development, often consisting of just a few founders and a rough business plan. Funding at this stage is often raised from personal savings, friends and family, and small seed funds.

Seed: In the seed stage, startups have typically developed a working prototype or minimum viable product (MVP) and are looking to raise capital to build out their team, refine their product, and begin marketing and selling. Seed funding can come from angel investors, early-stage venture capital funds, and crowdfunding platforms.

Series A: At the Series A stage, startups have typically achieved some initial traction and are looking to scale their operations and expand their customer base. Funding at this stage often comes from larger venture capital funds, as well as strategic investors and corporate venture capital funds.

Series B and C: At the Series B and C stages, startups are looking to accelerate their growth and expand their product offerings, often through acquisitions or strategic partnerships. Funding at these stages comes from larger venture capital firms and private equity funds.

IPO: An initial public offering (IPO) is the process by which a private company becomes publicly traded on a stock exchange. This allows the company to raise capital from a broad base of investors and gives its founders and early investors an opportunity to cash out. IPOs are typically undertaken by more mature startups with established revenue streams and a proven track record of growth.

Throughout each of these stages, startups may also consider alternative forms of financing, such as debt financing, strategic partnerships, and grants from government or non-profit organizations. The best approach will depend on the company's specific needs and goals, as well as the prevailing market conditions and investor sentiment.