Some firms choose not to use an investment bank advisor in mergers and acquisitions (M&A) transactions. We test whether this decision affects the merger announcement period returns. We compare the abnormal returns from a sample of 179 in-house acquisitions (in which either the acquirer or the target firm does not hire an investment bank advisor) to those of a matched sample of acquisitions (in which all firms hire an investment bank advisor). We find that not employing a financial advisor has no significant effect on the abnormal returns of acquiring firms but does reduce the abnormal returns of target firms. This relation holds even after controlling for various firm and merger characteristics.