Search giant Google reportedly offered to buy Twitter for between $2.5 billion and $4 billion.

[ad#Google Adsense 300×250 in story]Citing a source close to executives involved in the talks, Business Insider said Google isn’t the only suitor looking at Twitter. Sources said that Microsoft may have made an offer for the company as well.

A Twitter shareholder said the company turned down a $4 billion offer three months ago, but didn’t know if that came from Microsoft, Google, or another unknown company.

As Business Insider points out, talks of aquisitions in corporate America are the norm. They also characteristized the talks from Google as being a “casual offer to offer.”