* Sees tax rate at 14-15 vs 16 pct forecast last month
* Says to make 3-4 acquisitions in the next 18 months
* Expects 2018 adj. EPS of $1.35-$1.39 vs est $1.38
* Shares fall 1.7 pct (Adds conference call details, analysts comments, updates shares)
Feb 1 (Reuters) - Boston Scientific Corp forecast full-year earnings largely below Wall Street estimate and the medical device maker said it would likely do three or four acquisitions in the next 18 months.
The company's shares fell 1.7 percent in morning trading on Thursday. The stock had risen about 13 percent in January.
"We do have a pretty active M&A appetite," Chief Executive Michael Mahoney said on a conference call, adding the company expects to have about $500 million from its cash flow to spend in 2018.
Boston Scientific has focused on making smaller, bolt-on acquisitions to bolster its businesses. The company last week said it invested $90 million in privately held device maker Millipede Inc and entered into an acquisition option agreement.
The company bought Swiss medical device maker Symetis SA for $435 million last year.
"I would have expected a stronger earnings forecast but they want to spend this away," Glenn Novarro, an analyst at RBC Capital Markets, told Reuters.
Novarro expects the company to acquire early stage firms that it has invested in.
Boston Scientific, which reported in-line quarterly earnings, expects revenue of between $9.65 billion and $9.80 billion and adjusted earnings per share of $1.35 to $1.39 for 2018.
Analysts on average were expecting earnings of $1.38 per share and revenue of $9.61 billion, according to Thomson Reuters I/B/E/S.
The company estimates that its 2018 tax rate will be between 14 percent to 15 percent, lower than the 16 percent it projected last month.
NO SURPRISE QUARTER
Boston Scientific reported a net loss of $615 million, or 45 cents per share, for the fourth quarter ended Dec. 31, due to a $842 million charge from changes to the U.S. tax law.
Excluding items, the company earned 34 cents per share, in-line with analysts' average estimate.
Net sales rose 10 percent to $2.41 billion, just ahead of estimate of $2.38 billion.
The company reiterated that it expected to launch its Lotus Edge heart valves in the United States and European markets in 2019.
Boston Scientific recalled its Lotus range nearly a year ago, citing reports of problems with the locking mechanism.
"While we've all been focused on Lotus for ad nauseum, this is a diversified porfolio that's delivering," said BMO Capital Markets analyst Joanne Wuensch, adding that the quarter held "no surprises". (Reporting by Tamara Mathias in Bengaluru, Writing by Ankur Banerjee; Editing by Arun Koyyur and Sriraj Kalluvila)