It's time to take a look at Qualcomm's (NASDAQ:QCOM) tender offer for all shares of NXP Semiconductors (NASDAQ:NXPI). The number of shares committed to Qualcomm's $110 all-cash offer per share have been dwindling steadily from a peak in early March.

Did that trend continue in September? Let's have a look.

By the numbers

When NXP shareholders commit their stubs to Qualcomm's offer, the shares may be withdrawn at any time. That's been a popular option this summer:

Offer Update

NXP Shares Tendered

% of Shares Tendered

Sept. 22

10.9 million

3.2%

Aug. 24

23.5 million

6.9%

July 27

25.6 million

7.6%

June 28

42.2 million

12.5%

June 1

47.7 million

14.1%

May

50.3 million

14.9%

April

54.8 million

16.3%

March

58.0 million

17.2%

February

49.6 million

14.8%

Data source: Qualcomm.

If the tendered portion was shrinking in July, it's almost entirely dried up today. It looks like investors don't want to be stuck at the proposed buyout value of $110 per share any longer.

What's going on?

Earlier in the merger process, Qualcomm liked to share other buyout updates in these tender offer renewal statements. If there was a regulatory approval to announce, you would find them here. But that news flow stopped over the summer, with the last process update showing up at the end of June.

The European Commission launched an investigation of this deal's potential anticompetitive effects, then took that effort to the next level by pausing its investigation until further notice. The regulators are waiting for Qualcomm to provide more information about its post-merger business plans, and those intentions had better not include any distasteful cross-selling efforts to trip up competitors in NXP's and Qualcomm's respective wheelhouse markets.

Qualcomm has been in hot water with regulators around the world, who fear that the company might make NXP push the legal boundaries of salesmanship in similar ways.

So the deal isn't moving forward until NXP and Qualcomm can soothe the European Commission's fears, which might include a few concessions. The investigation could lead to Qualcomm and/or NXP shedding a couple of key units before tying the knot, and I fully expect to see some additional reporting requirements tossed into the mix.

Two men holding up large puzzle pieces with NXP's and Qualcomm's company logos.

Image source: Getty Images, Qualcomm, and NXP.

The growing opportunity cost of owning NXP

In the meantime, NXP shares have been frozen at roughly $110 for almost a full year while the rest of the very healthy chip market marched on. For example, occasional head-to-head rival STMicroelectronics (NYSE:STM) has seen its share prices more than doubling since last October and even stodgy old Texas Instruments (NASDAQ:TXN) has gained more than 25%. But NXP investors had to settle for a 10% gain. And even that small improvement has pushed share prices to nearly $113 per share -- 3% above the official deal price.

I used to think that the deal price was written in stone, but this exodus of tendered shares is telling me otherwise. NXP shareholders are uniting behind activist investor firm Elliot Management's demand for a higher price, and Qualcomm just might have to cough up a few more dollars in order to close this game-changing deal. If NXP shares stick to their current prices when all is said and done, that would work out to another $920 million out of Qualcomm's pockets for a total deal value of roughly $39 billion.

Mind you, Qualcomm is still highly motivated to make this deal work. It's just going to be a little more difficult than originally planned, and maybe more expensive as well.

Anders Bylund has no position in any of the stocks mentioned. The Motley Fool owns shares of Qualcomm. The Motley Fool recommends NXP Semiconductors. The Motley Fool has a disclosure policy.