The increase in operating assets was primarily due to a $77.8 million increase in accounts receivable due to increased sales and the impact of the new revenue recognition standard, a $34.1 million increase in inventories, and a $28.7 million increase in prepayments and other assets.
The decrease in operating liabilities was due to a $26.1 million decrease in accrued employee compensation due primarily to first quarter payments related to variable compensation, a $33.2 million decrease in income taxes, and $3.2 million of retirement plan contributions, partially offset by a $22.9 million increase in other accrued liabilities, a $19.4 million increase in accounts payable and a $9.8 million increase in deferred revenue and customer advance payments.
Investing activities during the nine months ended September 30, 2018 provided cash of $719.0 million due to $843.2 million and $934.1 million in proceeds from sales and maturities of marketable securities, respectively, proceeds from a government subsidy of $7.9 million for property, plant and equipment and proceeds from life insurance of $1.1 million related to the cash surrender value from the cancellation of Teradyne owned life insurance policies, partially offset by $809.5 million used for purchases of marketable securities, $169.5 million used for the acquisitions of MiR and Energid, and $88.3 million used for purchases of property, plant and equipment.
Financing activities during the nine months ended September 30, 2018 used cash of $626.0 million due to $562.3 million used for the repurchase of 13.8 million shares of common stock at an average price of $40.62 per share, $51.3 million used for dividend payments, $19.8 million used for payment related to net settlement of employee stock compensation awards, and $13.6 million used for a payment related to Universal Robots acquisition contingent consideration, partially offset by $21.0 million from the issuance of common stock under employee stock purchase and stock option plans.
In January 2019, May 2019, and August 2019, our Board of Directors declared a quarterly cash dividend of $0.09 per share. Dividend payments for the nine months ended September 29, 2019 were $46.3 million.
In January 2018, May 2018, and August 2018, our Board of Directors declared a quarterly cash dividend of $0.09 per share. Dividend payments for the nine months ended September 30, 2018 were $51.3 million.
In January 2018, our Board of Directors cancelled the December 2016 stock repurchase program and authorized a new stock repurchase program for up to $1.5 billion of common stock. We intend to repurchase $500 million in 2019. During the nine months ended September 29, 2019, we repurchased 8.8 million shares of common stock for $368.8 million at an average price of $41.93 per share. During the nine months ended September 30, 2018, we repurchased 13.8 million shares of common stock for $562.3 million at an average price of $40.62 per share. The cumulative repurchases under the $1.5 billion stock repurchase program as of September 29, 2019 totaled 30.4 million shares of common stock for $1,192.3 million at an average price per share of $39.18.
While we declared a quarterly cash dividend and authorized a share repurchase program, we may reduce or eliminate the cash dividend or share repurchase program in the future. Future cash dividends and stock repurchases are subject to the discretion of our Board of Directors, which will consider, among other things, our earnings, capital requirements and financial condition.
We believe our cash, cash equivalents and marketable securities balance will be sufficient to pay our quarterly dividend, execute our authorized share repurchase program and meet our working capital and expenditure needs for at least the next twelve months. Inflation has not had a significant long-term impact on earnings.
Equity Compensation Plans
As discussed in Note O: “Stock Based Compensation” in our 2018 Annual Report on Form
10-K,
we have a 1996 Employee Stock Purchase Plan and a 2006 Equity and Cash Compensation Incentive Plan (the “2006 Equity Plan”).
The purpose of the 1996 Employee Stock Purchase Plan is to encourage stock ownership by all eligible employees of Teradyne. The purpose of the 2006 Equity Plan is to provide equity ownership and compensation opportunities in Teradyne to our employees, officers, directors, consultants and/or advisors. Both plans were approved by our shareholders.
Recently Issued Accounting Pronouncements
On January 26, 2017, the FASB issued ASU
2017-04,
“Intangibles—Goodwill and Other (Topic 350): Simplifying the Accounting for Goodwill Impairment.”
The new guidance removes Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. Goodwill impairment will be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. All other goodwill impairment guidance will remain largely unchanged. Entities will continue to have the option to perform a qualitative assessment to determine if a quantitative impairment test is necessary. The same
one-step
impairment test will be applied to goodwill at all reporting units, even those with zero or negative carrying