A rollforward of the number of common limited partner, preferred limited partner and General Partner units follows.

	Limited partners
	Series A Preferred Units		Common		General Partner
Units, January 1, 2019		300,000		73,390,853		1,490,999
Conversion of General Partner economic interests		—		8,750,000		(1,490,999	)
Net units issued under the SMLP LTIP		—		554,458		—
Units, March 31, 2019		300,000		82,695,311		—

GP/IDR Exchange. On March 22, 2019, we cancelled our IDRs and converted our 2% economic GP interest to a non-economic GP interest in exchange for 8,750,000 SMLP common units which were issued to SMP Holdings (the “Equity Restructuring”). These units had a fair value of $84.5 million as of the transaction date (March 22, 2019). As a result of the Equity Restructuring, the general partner units and IDRs were eliminated, are no longer outstanding, and no longer participate in distributions of cash from SMLP. ECP continues to control the non-economic GP interest in SMLP.

At-the-market Program. In 2017, we executed an equity distribution agreement and filed a prospectus and a prospectus supplement with the SEC for the issuance and sale from time to time of SMLP common units having an aggregate offering price of up to $150.0 million (the "ATM Program"). These sales will be made (i) pursuant to the terms of the equity distribution agreement between us and the sales agents named therein and (ii) by means of ordinary brokers' transactions at market prices, in block transactions or as otherwise agreed between us and the sales agents. Sales of our common units may be made in negotiated transactions or transactions that are deemed to be at-the-market offerings as defined by SEC rules.

During the three months ended March 31, 2019, there were no transactions under the ATM Program. Following the effectiveness of the ATM Program registration statement and after taking into account the aggregate sales price of common units sold under the ATM Program through March 31, 2019, we have the capacity to issue additional common units under the ATM Program up to an aggregate $132.3 million.

Series A Preferred Units. In 2017, we issued 300,000 Series A Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units (the “Series A Preferred Units”) representing limited partner interests in the Partnership at a price to the public of $1,000 per unit as described in the 2018 Annual Report.

Cash Distributions Paid and Declared. We paid the following per-unit distributions during the three months ended March 31:

	Three months ended March 31,
	2019		2018
Per-unit distributions to unitholders	$	0.575	$	0.575

On April 25, 2019, the Board of Directors of our General Partner declared a distribution of $0.2875 per unit for the quarterly period ended March 31, 2019. This distribution, which totaled $23.8 million, will be paid on May 15, 2019 to unitholders of record at the close of business on May 8, 2019.

Incentive Distribution Rights. In March 2019, as a result of the Equity Restructuring, we cancelled our IDRs and converted our 2% economic GP interest to a non-economic GP interest in exchange for 8,750,000 newly issued SMLP common units, which were issued to SMP Holdings.

Immediately following the Equity Restructuring, SMP Holdings directly owned a 41.8% limited partner interest in SMLP and an affiliate of Energy Capital Partners II, LLC directly owned a 7.2% limited partner interest in SMLP.

For the three months ended March 31, 2018, our general partner held IDRs that entitled it to receive increasing percentage allocations, up to a maximum of 50%, of the cash we distributed from operating surplus in excess of $0.46 per unit per quarter.

Our payment of IDRs as reported in distributions to unitholders – general partner in the statement of partners' capital during the three months ended March 31 follow.

	Three months ended March 31,
	2019		2018
	(In thousands)
IDR payments	$	2,139	$	2,128

For the purposes of calculating net income attributable to General Partner in the statements of operations and partners' capital, the financial impact of IDRs was recognized in respect of the quarter for which the distributions were declared. For the purposes of calculating distributions to unitholders in the statements of partners' capital and cash flows, IDR payments were recognized in the quarter in which they are paid.